Tunnel support connection structure

Abstract

To provide a connecting structure for tunnel supports that allows one-touch joints in the tunnel longitudinal axis direction and has excellent strength.SOLUTION: A tunnel support connection structure comprises a first top joint plate provided on a first steel support, a second top joint plate provided on a second steel support, a male connection part having a male connection pin extending along the first top joint plate, and a female connection part having a female locking part into which the male connection pin can be inserted by relative movement between the first steel support and the second steel support in the tunnel longitudinal axis direction. The female connection part has a compressive axial force resisting part interposed between the first top joint plate and the second top joint plate when the first steel support and the second steel support are connected. The compressive axial force resisting part has a closed shape in a cross section passing through the axial direction of the support of the second steel support.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a connection structure for tunnel supports. [Background technology]

[0002] The NATM (New Austrian Tunneling Method) is a well-known construction method for building tunnels. When constructing tunnels using the NATM method, the ground surface exposed by tunnel excavation is quickly sealed with shoring. Tunnel shoring generally consists of shotcrete sprayed onto the ground surface, steel shoring assembled along the ground surface, and rock bolts driven into the ground from inside the tunnel.

[0003] Steel supports are usually made of H-shaped steel beams or similar. An arch-shaped tunnel support is formed by connecting a pair of (left and right) steel supports, which are divided into two around the tunnel, at their top ends. Steel supports are typically connected by using heavy machinery such as a jumbo drill to hold the steel supports, and then manually tightening bolts to the left and right steel supports near the top of the tunnel face. Manual bolt tightening is time-consuming and requires workers to enter the ground or directly below the primary shotcrete layer to perform the work.

[0004] Therefore, in recent years, a technology has been proposed in which a convex connecting portion is provided on the joint plate of one of the left and right steel supports, and a concave connecting portion is provided on the joint plate of the other steel support, and the convex connecting portion and the concave connecting portion are connected using a one-touch joint method by operating the arm of a heavy machine that grips the steel support (see, for example, Patent Document 1).

[0005] The connection structure described in Patent Document 1 connects a pair of steel supports by inserting a convex connecting part into a concave connecting part through relative movement between one steel support and the other in the tunnel crossing axis direction. The one-touch joint method in the tunnel crossing axis direction requires the left and right steel supports to be gradually brought closer to each other from positions some distance apart in the tunnel crossing axis direction, which requires a large amount of overexcavation during tunnel excavation. This overexcavation must ultimately be filled in with sprayed concrete or the like, so there is a demand to minimize overexcavation during tunnel excavation.

[0006] In this regard, Patent Document 2 discloses a connecting structure that includes a pair of boss portions into which a pair of connecting pins are inserted by relative movement between the first support member and the second support member in the tunnel longitudinal axis direction, and the pair of boss portions each include a locking mechanism that locks the connecting pins inserted into the boss portions. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2019-163663 [Patent Document 2] Japanese Patent Publication No. 2022-176546 Summary of the Invention [Problem to be solved by the invention]

[0008] It is true that one-touch joints in the tunnel longitudinal axis direction are possible with the steel shoring connection structure disclosed in Patent Document 2. However, the connection structure of the steel shoring that forms the tunnel shoring is required to have excellent strength to withstand large external forces, and from this perspective, there is room for improvement in the conventional connection structure.

[0009] The present invention has been made in consideration of the above-mentioned problems, and its purpose is to provide a connecting structure for tunnel supports that has excellent strength while allowing for one-touch joints in the tunnel longitudinal axis direction. [Means for solving the problem]

[0010] The technology disclosed herein is a connection structure of an arch-shaped tunnel support formed by connecting a first steel support and a second steel support, which are erected along a tunnel wall and divided into left and right halves, at their top ends, A first top joint plate provided on the end surface of the top end side of the first steel support; A second top joint plate provided on the end surface of the top end of the second steel support; A male connecting portion attached to the first top end joint plate, the male connecting portion having a male connecting pin extending along the first top end joint plate; a female connecting portion attached to the second top joint plate, the female connecting portion having a female locking portion into which the male connecting pin can be inserted and which can lock the inserted male connecting pin by relative movement between the first steel support and the second steel support in the tunnel longitudinal axis direction; Equipped with The female connection portion is a compressive axial force resisting portion interposed between the first top joint plate and the second top joint plate when the first steel support and the second steel support are connected, and further has a compressive axial force resisting portion formed as a resisting element against the compressive axial force while transmitting the compressive axial force between the first steel support and the second steel support, The compressive axial force resistance portion has a closed shape in a cross section passing through the support axial direction of the second steel support.

[0011] Here, the compressive axial force resistance portion may include a first steel plate and a second steel plate arranged opposite each other at a distance so as to extend from the surface of the second top joint plate in the support axis direction of the second steel support, and a steel abutment plate that connects the tip ends of the first steel plate and the second steel plate and abuts against the first top joint plate when the first steel support and the second steel support are connected.

[0012] In addition, the first steel plate and the second steel plate may be arranged at a distance from each other in the fore-and-aft direction of the second top end joint plate, the female locking portion may be provided on the first steel plate, and the first steel plate may be arranged closer to the rear edge of the second top end joint plate than the second steel plate.

[0013] The steel abutment plate may also be arranged parallel to the first top end joint plate.

[0014] Furthermore, at least a portion of the surface of the steel abutment plate may be formed as a guide surface inclined relative to the second top end joint plate, and the distance between the guide surface and the second top end joint plate may gradually decrease toward the rear end side of the steel abutment plate.

[0015] Furthermore, the surface of the first section of the steel abutment plate located on the connection end side with the second steel plate is formed as an abutment surface parallel to the second top end joint plate, and the surface of the second section located on the connection end side with the first steel plate is formed as a guide surface inclined with respect to the second top end joint plate, and the distance between the guide surface and the second top end joint plate may gradually decrease toward the connection end side with the first steel plate.

[0016] In addition, the male connecting portion may have a steel retaining plate extending from the surface of the first top end joint plate in the support axis direction of the first top end joint plate, and the male connecting pin may protrude from the steel retaining plate toward the front side in the fore-and-aft direction of the first top end joint plate.

[0017] The male coupling portion may further include a stiffening plate for suppressing distortion of the steel holding plate. [Effects of the Invention]

[0018] According to the present invention, a connecting structure for tunnel supports can be provided that allows for one-touch joints in the tunnel longitudinal axis direction and has excellent strength. [Brief explanation of the drawings]

[0019] [Figure 1] Figure 1 is a front view of the tunnel support. [Figure 2] FIG. 2 is a top view of the work vehicle. [Figure 3] FIG. 3 is a diagram illustrating the connection structure of the tunnel support. [Figure 4] FIG. 4 is a diagram illustrating the male coupling portion of the coupling structure. [Figure 5] FIG. 5 is a diagram illustrating the female coupling portion of the coupling structure. [Figure 6] FIG. 6 is a diagram showing the female locking portion in detail. [Figure 7] FIG. 7 is a diagram illustrating the state in which the first steel support and the second steel support are connected. [Figure 8] FIG. 8 is a diagram illustrating a connection structure of tunnel supports according to the first modification. [Figure 9] FIG. 9 is a diagram illustrating a connection structure of tunnel supports according to the second modification. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0021] <Embodiment 1> FIG. 1 is a front view of a tunnel support 10 according to the first embodiment. The tunnel support 10 is an arch-shaped H-shaped steel beam used in the NATM construction method. The tunnel support 10 is erected along the tunnel wall immediately after excavation to prevent the collapse of the ground exposed during tunnel excavation. Furthermore, the tunnel support 10 is typically installed at regular intervals in the extension direction of the tunnel (tunnel axis direction). The tunnel support 10 is formed in an arch shape by connecting a first steel support and a second steel support, which are divided into left and right halves, at their top ends. In this description, the side located on the right side when facing the tunnel face is referred to as the first steel support 10R, and the side located on the left side is referred to as the second steel support 10L. The first steel support 10R and the second steel support 10L may be interchanged.

[0022] The first steel support 10R has a main body 111, a first top joint plate 121, and a bottom plate 131. The main body 111 is a long H-shaped steel that curves along the tunnel wall, and is composed 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. A first top joint plate 121 is welded to the end face on the upper end (top end) side of the main body 111, and a bottom plate 131 is welded to the end face on the lower end side. For example, the first top joint plate 121 and the bottom plate 131 are formed as rectangular steel plates. A male connector is attached to the first top joint plate 121 of the first steel support 10R.

[0023] The second steel support 10L has a main body 112, a second top joint plate 122, and a bottom plate 132. The main body 112 is a long H-shaped steel that curves along the tunnel wall, and is composed 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. A second top joint plate 122 is welded to the end face on the upper end (top end) side of the main body 112, and a bottom plate 132 is welded to the end face on the lower end side. For example, the second top joint plate 122 and the bottom plate 132 are formed as rectangular steel plates. A female connector is attached to the second top joint plate 122 of the second steel support 10L. Details of the female connector will be described later. The symbol JS shown in Figure 1 indicates a connection structure including a male connector and a female connector. The details of the connecting structure JC will be described later.

[0024] FIG. 2 is a top view of a work vehicle 200 according to the first embodiment. The work vehicle 200 is equipped with an erector apparatus 100. The erector apparatus 100 is equipped with a pair of booms 17R, 17L. The pair of booms 17R, 17L can freely extend, retract, tilt, swing, and rotate by the operation of drive mechanisms attached to them. In addition, a pair of hands 18R, 18L are attached to the tip of each boom 17R, 17L. The pair of hands 18R, 18L can freely rotate and swing, and can detachably clamp and grip (hold) the first steel support 10R and the second steel support 10L, respectively.

[0025] When excavation in the new section of tunnel T and removal of debris are completed, the work vehicle 200, holding the first steel shoring 10R and the second steel shoring 10L in the hands 18R, 18L, is moved to the vicinity of the face FT. Then, a spraying device 300 mounted on the work vehicle 200 is used to spray primary concrete onto the exposed ground in the new section. Thereafter, the erector device 100, with the pair of hands 18R, 18L holding the first steel shoring 10R and the second steel shoring 10L, drives the booms 17R, 17L and the hands 18R, 18L to move the first steel shoring 10R and the second steel shoring 10L to predetermined positions, interconnects the top ends of the first steel shoring 10R and the second steel shoring 10L, and erects them in the predetermined positions. 2 indicates a tunnel longitudinal axis along the longitudinal direction of the tunnel T. The symbol X2 indicates a tunnel transverse axis that crosses the tunnel T.

[0026] Next, the connection structure JS of the tunnel shoring 10 in this embodiment will be described in detail. Figure 3 is a diagram illustrating the connection structure JS of the tunnel shoring 10. The connection structure JS of the tunnel shoring 10 comprises a first top end joint plate 121, a second top end joint plate 122, a male coupling portion 2 attached to the first top end joint plate 121, and a female coupling portion 3 attached to the second top end joint plate 122. Figure 3 is a schematic diagram of the connection structure JS viewed from above.

[0027] Figure 4 is a diagram illustrating the male coupling part 2 of the coupling structure JS according to embodiment 1. The upper part (A) of Figure 4 shows the male coupling part 2 as viewed from the front (as viewed from the direction of arrow A in Figure 3). The lower part (B) of Figure 4 shows the male coupling part 2 as viewed from the side (as viewed from the direction of arrow B in Figure 3).

[0028] The male connecting portion 2 is composed of a male connecting pin 21 extending along the first top end joint plate 121, a steel retaining plate 22 that holds the male connecting pin 21, a stiffening plate 23, etc.

[0029] The steel retaining plate 22 is welded to the first top joint plate 121 of the first steel shoring 10R so as to extend from the surface 121A of the first top joint plate 121 in the direction of the shoring axis (hereinafter referred to as the "first shoring axis") C1, which extends along the longitudinal direction of the first steel shoring 10R. For example, the steel retaining plate 22 is erected on the surface 121A of the first top joint plate 121 along the normal direction of the first top joint plate 121, which is perpendicular to the first shoring axis C1 direction of the first steel shoring 10R. The male connecting pin 21 protrudes from the surface 22A of the steel retaining plate 22 along the normal direction of the steel retaining plate 22. In other words, the male connecting pin 21 protrudes from the steel retaining plate 22 toward the front side (the leading edge 121D side) of the first top joint plate 121 in the fore-and-aft direction. As a result, the male connecting pin 21 is arranged so that its pin axis X3 is perpendicular to the direction of the first support axis C1 of the first steel support 10R and extends along the front-to-rear direction of the first top joint plate 121. In this embodiment, a single male connecting pin 21 is provided on the steel holding plate 22, but multiple male connecting pins 21 may be provided. In addition, the position of the male connecting pin 21 protruding from the steel holding plate 22 is not particularly limited, but in the example shown in FIG. 4, the male connecting pin 21 is located in the center of the steel holding plate 22 in the up-down direction. are placed.

[0030] Reference numeral 121A denotes the surface (outer surface) of the first top joint plate 121. Reference numeral 121B denotes the upper edge of the first top joint plate 121, reference numeral 121C denotes the lower edge of the first top joint plate 121, reference numeral 121D denotes the front edge of the first top joint plate 121, and reference numeral 121E denotes the rear edge of the first top joint plate 121. The upper edge 121B of the first top joint plate 121 faces the arch crown side of the tunnel wall when connecting the first steel support 10R and the second steel support 10L, and the lower edge 121C faces the opposite side, i.e., the interior space side. In addition, the leading edge 121D of the first top joint plate 121 faces the face FT side when connecting the first steel support 10R and the second steel support 10L, and the trailing edge 121E faces the opposite side, i.e., the entrance side of the tunnel T (the erector device 100 side).

[0031] The stiffening plates 23 are steel plates for suppressing distortion and deformation of the steel holding plate 22. In the example shown in FIG. 4, two stiffening plates 23 are installed on the back surface 22B side of the steel holding plate 22. The stiffening plates 23 are welded to the surface 121A of the first top joint plate 121 and the back surface 22B of the steel holding plate 22, and stiffen the steel holding plate 22 to increase its rigidity. The stiffening plates 23 have a roughly triangular planar shape when viewed from above, but the planar shape is not particularly limited. Furthermore, the positions at which the pair of stiffening plates 23 reinforce the steel holding plate 22 are not particularly limited. In the example shown in FIG. 4, one stiffening plate 23 is disposed in an upper region and one in a lower region relative to the center of the steel holding plate 22 in the vertical direction. Furthermore, in the example shown in FIG. 4, each stiffening plate 23 extends along the lateral direction of the steel holding plate 22.

[0032] Figure 5 is a diagram illustrating the female coupling portion 3 of the coupling structure JS according to embodiment 1. The upper part (A) of Figure 5 shows the female coupling portion 3 as viewed from the front (as viewed from the direction of arrow C in Figure 3). The lower part (B) of Figure 5 shows the male coupling portion 2 as viewed from the side (as viewed from the direction of arrow D in Figure 3).

[0033] The female connecting portion 3 is equipped with a compressive axial force resisting portion 30 and a female locking portion 40 attached to the surface 122A side of the second top joint plate 122 of the second steel support 10L. The compressive axial force resisting portion 30 is a member interposed between the first top joint plate 121 and the second top joint plate 122 when the first steel support 10R and the second steel support 10L are connected, and is formed as a resisting element against the compressive axial force while transmitting the compressive axial force between the first steel support 10R and the second steel support 10L. The female locking portion 40 is configured so that a male connecting pin 21 can be inserted therein and so that the inserted male connecting pin 21 can be locked. As will be described in more detail later, the female locking portion 40 allows the male connecting pin 21 to be inserted and locked by relative movement with the first steel support 10R and the second steel support 10L in the direction of the tunnel longitudinal axis X1.

[0034] Here, reference numeral 122A denotes the surface (outer surface) of the second top joint plate 122. Reference numeral 122B denotes the upper edge of the second top joint plate 122, reference numeral 122C denotes the lower edge of the second top joint plate 122, reference numeral 122D denotes the front edge of the second top joint plate 122, and reference numeral 122E denotes the rear edge of the second top joint plate 122. The upper edge 122B of the second top joint plate 122 faces the arch crown side of the tunnel wall when connecting the first steel support 10R and the second steel support 10L, and the lower edge 122C faces the opposite side, i.e., the interior space side. In addition, the leading edge 122D of the second top joint plate 122 faces the face FT side when connecting the first steel support 10R and the second steel support 10L, and the trailing edge 122E faces the opposite side, i.e., the entrance side of the tunnel T (the erector device 100 side).

[0035] The compressive axial force resistance portion 30 has a closed shape in a cross section passing through the support axis (hereinafter referred to as the "second support axis") C2 direction extending along the longitudinal direction of the second steel support 10L. In the example shown in Fig. 3, the compressive axial force resistance section 30 is composed of a first steel plate 31 and a second steel plate 32 arranged opposite each other with a gap in between, and a steel abutment plate 33 connecting the leading ends of these plates. The first steel plate 31, the second steel plate 32, and the steel abutment plate 33 constituting the compressive axial force resistance section 30 are rigidly joined together by welding or the like, and have a roughly U-shape when viewed from above. In the example shown in Fig. 3, the steel abutment plate 33 is provided parallel to the second top joint plate 122, and is configured to abut against the first top joint plate 121 when the first steel shoring 10R and the second steel shoring 10L are connected.

[0036] The first steel plate 31 and the second steel plate 32 are joined at their base ends to the second top joint plate 122 by welding or the like so that they extend from a surface 122A of the second top joint plate 122 in the direction of the second support axis C2. The first steel plate 31 serves as a retaining plate that holds the female locking portion 40. The female locking portion 40 is joined to the back surface of the first steel plate 31 by welding or the like while being stored in the inner space of the compressive axial force resistance portion 30.

[0037] The first steel plate 31 and the second steel plate 32 are arranged at an interval in the direction of the tunnel longitudinal axis X1 when connecting the first steel support 10R and the second steel support 10L, and the second steel plate 32 is provided closer to the face FT in the direction of the tunnel longitudinal axis X1 than the first steel plate 31. In other words, the first steel plate 31 and the second steel plate 32 are arranged at an interval in the front-to-rear direction of the second top joint plate 122, and the first steel plate 31 is provided in a position closer to the trailing edge 122E of the second top joint plate 122 than the second steel plate 32. In the example shown in FIG. 3, the second steel plate 32 is arranged near the leading edge 122D of the second top joint plate 122, and the first steel plate 31 is arranged in a position closer to the trailing edge 122E of the second top joint plate 122.

[0038] FIG. 6 is a diagram illustrating the female locking portion 40 in detail. The female locking portion 40 has a cylindrical metal casing 41. The casing 41 is attached to the back surface of the first steel plate 31 by welding or the like. The front end of the casing 41 is formed as an open end, and a storage chamber 42 is formed inside the casing 41. The first steel plate 31 has an insertion opening 48 for inserting the male connecting pin 21 into the storage chamber 42 of the casing 41 at a position corresponding to the open end of the casing 41 in the female locking portion 40. The insertion opening 48 penetrates the first steel plate 31 in the thickness direction. The casing axis X4 of the casing 41 in the female locking portion 40 is perpendicular to the second support axis C2 direction of the second steel support 10L and extends along the front-to-rear direction of the second top joint plate 122.

[0039] A tapered hole 43 having a tapered surface 43a whose inner diameter gradually decreases from the rear end to the front end is formed at the tip (front) of the storage chamber 42 in the female locking part 40. A spring storage section 42a is formed in the middle of the storage chamber 42, and a female screw 45 is formed on the inner periphery of the rear part of the storage chamber 42.

[0040] Furthermore, divided locking pieces 46 are arranged within the tapered hole 43 so as to be slidable in the axial direction. The outer surfaces of the locking pieces 46 are formed as tapered surfaces 46a that are slidable along the tapered surfaces 43a of the tapered hole 43. The tapered surfaces 46a of the locking pieces 46 gradually increase in outer diameter from the tip to the rear. Furthermore, a female thread 46b is formed on the inner surface of each locking piece 46. The female threads 46b are multiple circumferential female locking grooves arranged side by side on the inner surface of each locking piece 46. The female threads 46b are formed in an arc centered on the axis of the casing 41 and in a direction along the axis. As described above, a female threaded hole is formed by the multiple locking pieces 46. When the tapered surfaces 46a of each locking piece 46 move back along the tapered surfaces 43a of the tapered hole 43, the diameter of the female threaded hole is enlarged, and when they move forward (forward), the diameter of the female threaded hole is reduced. The female threads 46b formed on the inner surface of each locking piece 46 can be engaged with the male threads 21A formed on the outer periphery of the male connecting pin 21 (see FIG. 3).

[0041] Furthermore, in the spring storage section 42a of the storage chamber 42, pressure springs 44, which are pressure members that press (elastically bias) the locking pieces 46 forward (forward), are stored in a compressed state between the cover plate 49 and spring receivers 47 provided at the rear ends of the locking pieces 46, and the pressure of the pressure springs 44 constantly presses the locking pieces 46 forward. The cover plate 49 can be held in a compressed state by being screwed into a female screw 45 engraved on the inner periphery 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 using a hexagonal wrench or the like.

[0042] Next, a procedure for connecting the first steel support 10R and the second steel support 10L using the above-described connecting structure JS will be described. In this embodiment, the booms 17R, 17L and the hands 18R, 18L of the erector device 100 are operated to move the female locking portion 40 provided on the female connecting portion 3 (compression axial force resisting portion 30) and the male connecting pin 21 provided on the male connecting portion 2 relatively close to each other along the tunnel longitudinal axis X1. Then, the male connecting pin 21 is inserted into the storage chamber 42 of the female locking portion 40 through the insertion opening 48 in the first steel plate 31 of the female connecting portion 3. As a result, the male thread 21A of the male connecting pin 21 is locked by the locking piece 46 of the female locking portion 40. As a result, the first steel support 10R and the second steel support 10L are connected at their top ends. In this way, by moving the male connecting pin 21 and the female locking portion 40 relative to each other along the direction of the tunnel longitudinal axis X1, the first steel support 10R and the second steel support 10L can be connected with a single touch.

[0043] 3 indicates a first distance between the surface 121A of the first crown joint plate 121 and the pin axis X3 of the male connecting pin 21. Furthermore, reference symbol L2 indicates a second distance between the surface 33A of the steel abutment plate 33 in the compressive axial force resisting section 30 and the casing axis X4 in the female locking section 40. For example, the first distance L1 and the second distance L2 are set to be equal. This allows the first steel support 10R and the second steel support 10L to move relatively along the tunnel longitudinal axis X1 while sliding the surface 33A of the steel abutment plate 33 and the surface 121A of the first crown joint plate 121, thereby making it possible to easily insert the male connecting pin 21 into the female locking section 40.

[0044] In the connection structure JS of the tunnel support 10 in this embodiment, by adopting a push-in joint system along the tunnel longitudinal axis X1, it is possible to reduce the amount of over-excavation during tunnel excavation compared to a push-in joint system along the tunnel transverse axis. As a result, it is possible to shorten the construction period required for tunnel construction and reduce labor and costs.

[0045] 7 is a diagram illustrating the state in which the first steel shoring 10R and the second steel shoring 10L are connected. According to the connection structure JS for the tunnel shoring 10 in this embodiment, while enabling one-touch joints along the tunnel longitudinal axis X1 as described above, the first steel shoring 10R and the second steel shoring 10L are provided with a first top joint plate 121 and a second top joint plate 122 on their respective top-side end faces, and a compressive axial force resisting section 30 is provided between the first top joint plate 121 and the second top joint plate 122 when the first steel shoring 10R and the second steel shoring 10L are connected. The connection structure JS for the tunnel shoring 10 allows the compressive axial force between the first steel shoring 10R and the second steel shoring 10L to be transmitted by the compressive axial force resisting section 30. The compressive axial force resistance section 30 has a closed shape in a cross section passing through the direction of the second support axis C2 in the second steel support 10L, and therefore has excellent strength and durability, and can resist a larger compressive axial force acting between the first steel support 10R and the second steel support 10L.

[0046] In particular, the compressive axial force resistance portion 30 connects the tip ends of the first steel plate 31 and the second steel plate 32 that are extended from the second top end joint plate 122 in the direction of the second support axis C2, and and a steel abutment plate 33 that abuts against the first top joint plate 121 when the first steel shoring 10R and the second steel shoring 10L are connected. In this way, by adopting a structure in which the first steel plate 31 and the second steel plate 32 are interposed between the second top joint plate 122 and the steel abutment plate 33 and the steel abutment plate 33 abuts against the first top joint plate 121, the strength and rigidity of the compressive axial force resisting section 30 can be increased.

[0047] Furthermore, in this embodiment, the first steel plate 31 and the second steel plate 32 are arranged at intervals in the fore-and-aft direction of the second top joint plate 122, and the female locking portion 40 is held on the first steel plate 31 located on the rear edge 122E side of the second top joint plate 122.This makes it easy to insert the male connecting pin 21 into the female locking portion 40 from the tunnel entrance side in the direction of the tunnel longitudinal axis X1 when connecting the first steel support 10R and the second steel support 10L, resulting in excellent workability.

[0048] Furthermore, the steel abutment plate 33 in the compressive axial force resistance section 30 is provided parallel to the second top joint plate 122. This allows the steel abutment plate 33 to abut entirely against the surface 121A of the first top joint plate 121 when the first steel support 10R and the second steel support 10L are connected. This further increases the strength and rigidity of the compressive axial force resistance section 30.

[0049] Note that various modifications can be adopted for the connecting structure JS of the tunnel support 10 according to the first embodiment. For example, the first steel plate 31 in the compressive axial force resisting section 30 may be disposed near the rear edge 122E of the second crown joint plate 122. In the following modifications, the same members as those in the above-described embodiment are designated by the same reference numerals, and detailed explanations thereof will be omitted.

[0050] <Variation 1> FIG. 8 is a diagram illustrating a connection structure JS of a tunnel support 10 according to Modification 1. In the connection structure JS according to Modification 1, the compressive axial force resisting portion 30A of the female coupling portion 3 differs from the compressive axial force resisting portion 30 described above. In the compressive axial force resisting portion 30A according to Modification 1, at least a portion of the surface 33A of the steel abutment plate 33 is formed as a guide surface GF inclined relative to the second crown joint plate 122, and the distance between this guide surface GF and the second crown joint plate 122 gradually decreases toward the rear end. In FIG. 8, the entire surface 33A of the steel abutment plate 33 is formed as a guide surface GF. Reference symbol L2' shown in FIG. 8 denotes a second distance between the surface 33A of the steel abutment plate 33 and the casing axis X4 of the female locking portion 40 at the front end position of the steel abutment plate 33. For example, the first distance L1 and the second distance L2' are set to be equal. This makes it possible to easily insert the male connecting pin 21 into the female locking portion 40 by sliding the guide surface GF of the steel abutment plate 33 against the surface 121A of the first top end joint plate 121 while moving the first steel support 10R and the second steel support 10L relative to each other along the tunnel longitudinal axis X1.

[0051] When connecting the first steel support 10R and the second steel support 10L, the surface 121A of the first top joint plate 121 can be guided by sliding it along the guide surface GF (surface 33A of the steel abutment plate 33). This guide function corrects any planar misalignment between the casing axis X4 of the female locking portion 40 and the pin axis X3 of the male connecting pin 21, and allows the male connecting pin 21 to be guided into the insertion port 48 of the female connecting portion 3.

[0052] <Variation 2> 9 is a diagram illustrating a connection structure JS of a tunnel support 10 according to Modification 2. In the connection structure JS according to Modification 2, the compressive axial force resistance portion 30B of the female coupling portion 3 differs from the compressive axial force resistance portions 30 and 30A described above.

[0053] The steel abutment plate 33 in the compressive axial force resistance portion 30B is located on the connection end side with the second steel plate 32. The surface 33A1 of the first section, where the steel retaining plate 22 is placed, is formed as a contact surface CF parallel to the second top joint plate 122, and the surface 33A2 of the second section, located on the connection end side with the first steel plate 31, is formed as a guide surface GF inclined with respect to the second top joint plate 122. The guide surface GF is spaced from the second top joint plate 122 gradually decreasing toward the connection end side with the first steel plate 31. Symbol L2" shown in FIG. 9 is a second separation dimension between the contact surface CF (surface 33A1) and the casing axis X4 of the female locking portion 40. For example, the first separation dimension L1 and the second separation dimension L2" are set to be equal. Symbol L3 is a third separation dimension between the surface 22A of the steel retaining plate 22 and the front edge 121D of the first top joint plate 121. Symbol L4 is a fourth distance between the boundary position between the first and second sections of the steel abutment plate 33 (i.e., the front end position of the guide surface GF) and the rear edge 122E of the second top joint plate 122. For example, the third distance L3 and the fourth distance L4 are set to be equal. This makes it possible to easily insert the male connecting pin 21 into the female locking portion 40 by moving the first steel support 10R and the second steel support 10L relatively along the tunnel longitudinal axis X1 while sliding the guide surface GF of the steel abutment plate 33 against the surface 121A of the first top joint plate 121.

[0054] The above describes embodiments of the present invention, but these are merely examples, and the present invention is not limited to these. Various modifications based on the knowledge of those skilled in the art are possible as long as they do not deviate from the spirit of the claims. [Explanation of symbols]

[0055] 2...Male connection part 3...Female connection part 10. Tunnel support 10R...No. 1 steel shoring 10L...Second steel shoring JS...Connection structure 21 Male connecting pin 22...Steel retaining plate 23... Stiffening plate 30. Compression axial force resistance section 31. First steel plate 32...Second steel plate 33...Steel contact plate 40...Female locking part 121···First top joint plate 122···Second top joint plate

Claims

1. A connecting structure of arch-shaped tunnel supports formed by connecting the first and second steel supports, which are erected along the tunnel wall and divided into left and right halves, at their top ends. A first top joint plate provided on the end surface of the top end side of the first steel support; A second top joint plate provided on the end surface of the top end side of the second steel support; A male connecting portion attached to the first top end joint plate, the male connecting portion having a male connecting pin extending along the first top end joint plate; a female connecting portion attached to the second top joint plate, the female connecting portion having a female locking portion into which the male connecting pin can be inserted and which can lock the inserted male connecting pin by relative movement between the first steel support and the second steel support in the tunnel longitudinal axis direction; Equipped with The female connection portion is a compressive axial force resistance portion interposed between the first top joint plate and the second top joint plate when the first steel support and the second steel support are connected, and further has a compressive axial force resistance portion formed as a resisting element against the compressive axial force while transmitting the compressive axial force between the first steel support and the second steel support, The compressive axial force resistance portion has a closed shape in a cross section passing through the support axial direction of the second steel support, Tunnel support connection structure.

2. The compressive axial force resistance portion is A first steel plate and a second steel plate arranged opposite to each other at an interval so as to extend from the surface of the second top joint plate in the support axial direction of the second steel support; A steel abutment plate that connects the tip sides of the first steel plate and the second steel plate and abuts against the first top joint plate when the first steel support and the second steel support are connected; having The tunnel support connection structure according to claim 1.

3. The first steel plate and the second steel plate are arranged at intervals in the front-to-rear direction of the second top end joint plate, The female locking portion is provided on the first steel plate, and the first steel plate is positioned closer to the rear edge of the second top end joint plate than the second steel plate. A tunnel support connection structure according to claim 2.

4. 4. The tunnel support connection structure according to claim 2 or 3, wherein the steel abutment plate is arranged parallel to the first top end joint plate.

5. At least a part of the surface of the steel abutment plate is formed as a guide surface inclined with respect to the second top end joint plate, The guide surface has a distance from the second top end joint plate that gradually decreases toward the rear end side of the steel abutment plate. A tunnel support connection structure according to claim 2 or 3.

6. The surface of the first section of the steel abutment plate located on the connection end side with the second steel plate is formed as an abutment surface parallel to the second top end joint plate, and the surface of the second section located on the connection end side with the first steel plate is formed as a guide surface inclined with respect to the second top end joint plate, The guide surface is spaced apart from the second top end joint plate toward the connection end with the first steel plate. The distance between them is gradually decreasing, A tunnel support connection structure according to claim 2 or 3.

7. The male coupling portion has a steel retaining plate extending from the surface of the first top joint plate in the support axial direction of the first top joint plate, The male connecting pin protrudes from the steel retaining plate toward the front side in the front-to-rear direction of the first top end joint plate. A tunnel support connection structure according to any one of claims 1 to 3.

8. The male coupling portion further includes a stiffening plate for suppressing distortion of the steel retaining plate. A tunnel support connection structure according to claim 7.

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