Steel support structure

Abstract

To provide a joint structure for a steel shoring that can easily connect left and right shoring members.SOLUTION: The present invention comprises a pair of connecting pins 5a and 5b attached to a top end of a first shoring member 1a facing a face side in the axial direction of a tunnel, and attached to a top end of a second shoring member 1b toward a portal side in the axial direction of the tunnel, a pair of boss portions 6a and 6b attached to the top end portion of the first shoring member 1a so as to be insertable from the face side in the axial direction of the tunnel, attached to the top end portion of the second shoring member 1b so as to be insertable from the portal side in the axial direction of the tunnel, and into which a pair of connecting pins 5a, 5b are respectively inserted by relative movement of the first shoring member 1a and the second shoring member 1b in the axial direction of the tunnel. The pair of boss portions 6a and 6b are respectively provided with locking mechanisms for locking the connecting pins 5a and 5b inserted into the boss portions 6a and 6b.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a joint structure for a steel support. [Background technology]

[0002] In tunnel excavation and support construction work using the New Austrian Tunneling Method (NATM), steel supports are made by bending H-shaped steel materials into the arch shape of the tunnel. Steel supports are made by connecting two support members on the left and right at the top center (top) to form an arch shape, and then erecting this on the cross section of the tunnel.

[0003] The joint structure of steel support structures typically involves butting together joint plates located at the top ends of the left and right support components and connecting them with bolts, but in order to connect the bolts, workers had to enter just below the ground to do so.

[0004] Therefore, a joint structure for steel shoring that avoids bolt fastening by workers has been proposed (for example, see Patent Document 1). In Patent Document 1, a male joint plate having a male coupling portion is provided at the top end of one shoring member, and a female joint plate having a female coupling portion is provided at the top end of the other shoring member, and the abutting surfaces of the male joint plate and the female joint plate are slid relative to each other in the lateral direction of the abutting surfaces while in abutment with each other, whereby the male joint portion is engaged with the female coupling portion. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2018-178452 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the conventional technology, the male joint plate and the female joint plate are slid relative to each other while their contact surfaces are in contact with each other, and the female connector and the male connector formed on each contact surface are connected. Therefore, the operator of the erector device that erects the steel support needs to accurately align the left and right directions while shifting the left and right support members back and forth, which requires skilled techniques.

[0007] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a joint structure for steel support that can solve the above-mentioned problems and easily connect the left and right support members. [Means for solving the problem]

[0008] The joint structure of a steel support of the present invention is a joint structure of a steel support formed by connecting a first support member and a second support member divided into left and right halves at their top ends, and comprises a pair of connecting pins attached to the top end of the first support member toward the face side in the tunnel axis direction and attached to the top end of the second support member toward the portal side in the tunnel axis direction, and a pair of boss portions attached to the top end of the first support member so as to be insertable from the face side in the tunnel axis direction and attached to the top end of the second support member so as to be insertable from the portal side in the tunnel axis direction, into which the pair of connecting pins are respectively inserted by relative movement between the first support member and the second support member in the tunnel axis direction, and each of the pair of boss portions is equipped with a locking mechanism for locking the connecting pins inserted into the boss portions. Furthermore, in the joint structure of the steel support of the present invention, the connecting pin may be formed with a conical tapered surface whose diameter becomes smaller toward the tip, and the hollow portion of the boss portion may be formed with an annular tapered surface whose diameter becomes larger toward the insertion opening. Furthermore, in the joint structure of the steel support of the present invention, the locking mechanism may be a locking member installed so as to protrude into the hollow portion of the boss portion by the force of a spring, and the connecting pin may be locked to the boss portion by fitting the locking member into a groove portion formed in the connecting pin. Furthermore, in the joint structure for steel support of the present invention, the locking member may be a ball plunger. Effect of the Invention

[0009] According to the present invention, the first support member and the second support member can be connected simply by moving the first support member and the second support member relative to each other so that the connecting pin is inserted into the boss portion, thereby allowing for errors during erection and achieving the effect of easily connecting the first support member and the second support member. [Brief description of the drawings]

[0010] [Figure 1] 1 is a perspective view showing a configuration of a first embodiment of a steel support according to the present invention. [Diagram 2] FIG. 2 is an enlarged perspective view showing the configuration of a joint structure of the steel support shown in FIG. [Diagram 3] FIG. 2 is a cross-sectional view showing the configuration of a joint structure of the steel support shown in FIG. [Figure 4] FIG. 2 is a diagram showing an example of the configuration of an erector device for erecting the steel support shown in FIG. [Diagram 5] 4 is an explanatory diagram illustrating a coupling operation of the coupling structure shown in FIG. 3. [Figure 6] 5A and 5B are diagrams showing another example of the locking mechanism for locking the connecting pin to the boss portion shown in FIG. 3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Next, a mode for carrying out the present invention (hereinafter simply referred to as an "embodiment") will be specifically described with reference to the drawings.

[0012] 1, the steel support 1 of this embodiment is an arch-shaped H-shaped steel that is erected along the tunnel wall immediately after excavation to prevent the collapse of the ground exposed during tunnel excavation, and is installed at specified intervals along the tunnel axis. The steel support 1 is erected in a divided state into a first support member 1a arranged on the right side toward the tunnel face and a second support member 1b arranged on the left side toward the tunnel face, and the top ends (upper center) are connected to form an arch shape.

[0013] The first support member 1a and the second support member 1b are H-shaped steel beams having a predetermined curved shape that is symmetrical on the left and right, and a joint structure is provided at the top end of each beam to connect the first support member 1a and the second support member 1b.

[0014] 2 and 3, this joint structure includes a connecting pin 5a and a boss portion 6a attached to the top end of the first shoring member 1a, and a connecting pin 5b and a boss portion 6b attached to the top end of the second shoring member 1b. The connecting pin 5b of the second shoring member 1b is inserted into the boss portion 6a of the first shoring member 1a, and the connecting pin 5a of the first shoring member 1a is inserted into the boss portion 6b of the second shoring member 1b, and the two are locked together, connecting the first shoring member 1a and the second shoring member 1b. FIG. 2 is an enlarged view of the top end. FIG. 3 is a cross-sectional view taken along a plane passing through the axes of the boss portions 6a, 6b and the connecting pins 5a, 5b.

[0015] The H-shaped steel constituting the first support member 1a consists of opposing upper and lower flanges 2a and 3a, and a web 4a that is perpendicular to the upper and lower flanges 2a and 3a and connects the upper and lower flanges 2a and 3a, and the flange surfaces of the upper and lower flanges 2a and 3a are curved into a specified shape. The first support member 1a is installed so that the upper flange 2a is placed on the natural ground side and the upper and lower flanges 2a and 3a are parallel to the tunnel axis direction.

[0016] A cylindrical connecting pin 5a and a cylindrical boss portion 6a are attached to the top end of the first support member 1a using a support plate 7a. The support plate 7a is made of a steel plate, and is placed across the wellhead end of the upper flange 2a and the lower flange 3a and fixed by welding or the like. The reference numeral 73a in Fig. 3 denotes a reinforcing plate that reinforces the fixing of the support plate 7a.

[0017] The support plate 7a has an extension surface 71a extending from the top end of the first support member 1a, and a connecting pin 5a is erected on the extension surface 71a of the support plate 7a and parallel to the upper flange 2a and lower flange 3a (in the tunnel axis direction) toward the face side.

[0018] An opening 41a and an opening 72a through which the boss portion 6a penetrates are formed in the web 4a and the support plate 7a at the top end of the first support member 1a, respectively. The boss portion 6a penetrates the opening 41a and the opening 72a, and is fixed to the web 4a and the support plate 7a by welding or the like in a state in which the hollow portion 61 is parallel to the upper flange 2a and the lower flange 3a (in the tunnel axis direction) and the connecting pin 5b of the second support member 1b can be inserted from the face side.

[0019] The H-shaped steel constituting the second support member 1b consists of opposing upper and lower flanges 2b and 3b, and a web 4b that is perpendicular to the upper and lower flanges 2b and 3b and connects the upper and lower flanges 2b and 3b, and the flange surfaces of the upper and lower flanges 2b and 3b are curved into a specified shape. The second support member 1b is installed so that the upper flange 2b is placed on the natural ground side and the upper and lower flanges 2b and 3b are parallel to the tunnel axis direction.

[0020] A cylindrical connecting pin 5b and a cylindrical boss portion 6b are attached to the top end of the second support member 1b using a support plate 7b. The support plate 7b is made of a steel plate, and is placed across the face side ends of the upper flange 2b and the lower flange 3b and fixed by welding or the like. The reference numeral 73b in Fig. 3 denotes a reinforcing plate that reinforces the fixing of the support plate 7b.

[0021] The support plate 7b has an extension surface 71b extending from the top end of the second support member 1b, and a connecting pin 5b is erected on the extension surface 71b of the support plate 7b, facing toward the tunnel entrance side and parallel to the upper flange 2b and the lower flange 3b (in the tunnel axis direction).

[0022] An opening 41b and an opening 72b through which the boss portion 6b penetrates are formed in the web 4b and the support plate 7b at the top end of the second support member 1b, respectively. The boss portion 6b penetrates the opening 41b and the opening 72b, and the hollow portion 61 is fixed to the web 4b and the support plate 7b by welding or the like in a state in which the connecting pin 5a of the first support member 1a can be inserted from the tunnel mouth side in parallel with the upper flange 2b and the lower flange 3b (in the tunnel axis direction).

[0023] In this embodiment, the connecting pin 5a of the first shoring member 1a and the connecting pin 5b of the second shoring member 1b have the same configuration, and the boss portion 6a of the first shoring member 1a and the boss portion 6b of the second shoring member 1b have the same configuration. Therefore, the common configurations will be described below with the reference characters "a" and "b" omitted.

[0024] The connecting pin 5 has a cylindrical portion that is longer than the width of the upper flange 2 and the lower flange 3, and has three rows of grooves 51 formed at predetermined intervals in the circumferential direction, and a tip portion that is formed with a conical tapered surface 52 whose diameter decreases toward the tip. There is no particular limit to the number of rows of grooves 51, and there may be one or two rows, or four or more rows.

[0025] The hollow portion 61 of the boss portion 6 includes a cylindrical portion in which the ball plunger 8 is disposed, and an insertion portion in which an annular tapered surface 62 whose diameter increases toward the insertion opening of the connecting pin 5 is formed.

[0026] Ball plunger 8 is installed so that a ball, which is a spring-biased locking member, protrudes into hollow portion 61, and is arranged in the axial direction at the same intervals as groove portions 51 of connecting pin 5. This allows the balls of ball plunger 8 to fit into the groove portions 51 of connecting pin 5 inserted into hollow portion 61 of boss portion 6, and connects connecting pin 5 to boss portion 6. In other words, ball plunger 8 of boss portion 6 that locks groove portions 51 of connecting pin 5 functions as a locking mechanism.

[0027] Furthermore, when the connecting pin 5 is inserted, the ball of the ball plunger 8 comes into contact with the circumferential surface of the connecting pin 5 while being biased by a spring, so that the ball plunger 8 also functions as a guide mechanism. Note that, if a plurality of ball plungers 8 are installed at equal intervals in the circumferential direction of the central axis of the hollow portion 61, the axes of the hollow portion 61 of the boss portion 6 and the connecting pin 5 can be aligned, allowing for more effective guiding.

[0028] An erector device 9 shown in Fig. 4 is used to erect the steel support 1. The erector device 9 is configured with a pair of booms 91 and a clamp 92 attached to the tip of the booms 91. The pair of booms 91 are configured using a swinging member such as a hydraulic cylinder so that they can swing freely over a wide angle, including up and down and left and right. The clamp 92 connected to the tip of the booms 91 is also configured using a swinging member such as a hydraulic cylinder so that it can grip the first support member 1a, the second support member 1b, etc.

[0029] As shown in Fig. 4, in addition to the pair of booms 91, a pair of sub-booms 93 each having a clamp 92 at its tip may be provided. The case where the sub-booms 93 are provided is used when erecting a large steel support 1 in a relatively large tunnel.

[0030] The first support member 1a and the second support member 1b are grasped by clamps 92 attached to each of a pair of booms 91 (sub-booms 93), and connected to form an arch shape, thereby erecting the steel support 1 at a designated position within the tunnel.

[0031] The first support member 1a and the second support member 1b are connected by holding the first support member 1a and the second support member 1b on a pair of booms 91, respectively, and placing them at the installation location with their top ends shifted in the tunnel axis direction, as shown in Figures 2 and 3.

[0032] Then, the first support member 1a and the second support member 1b are moved relative to each other in the tunnel axis direction so that the tip portion of the connecting pin 5, on which the conical tapered surface 52 is formed, is guided into the insertion portion of the boss portion 6, on which the annular tapered surface 62 is formed.

[0033] Then, even if the axes of the connecting pin 5 and the boss portion 6 are misaligned, the tip of the connecting pin 5 is guided to the cylindrical portion of the boss portion 6 where the ball plunger 8 is disposed, by the annular tapered surface 62 and the conical tapered surface 52 of the boss portion 6, as shown in Figure 5(a). Therefore, even if errors occur in positioning using a target and a total station, or in positioning using motion capture technology with a marker and a camera, it is tolerable.

[0034] 5(b), the balls of the ball plunger 8 are fitted into each of the three rows of grooves 51 of the connecting pin 5 inserted into the hollow portion 61 of the boss portion 6, and the first support member 1a and the second support member 1b are moved relatively in the tunnel axial direction until the connecting pin 5 is locked into the boss portion 6. This makes it possible to safely connect the first support member 1a and the second support member 1b and erect the steel support 1 without workers having to enter directly below the natural ground to join the two bolts.

[0035] Since the connecting pin 5 is longer than the width of the upper flange 2 and the lower flange 3, when the first support member 1a and the second support member 1b are connected, the tip of the connecting pin 5 protrudes from the boss portion 6 as shown in Fig. 5(b). The connection can be confirmed by visually checking the protruding tip of the connecting pin 5. Furthermore, by coloring the tip of the connecting pin 5 a different color from the boss portion 6, it is easy to guide the connecting pin 5 during insertion and to confirm the connection.

[0036] In this embodiment, the locking mechanism is constituted by the groove 51 of the connecting pin 5 and the ball plunger 8, so that the lock between the groove 51 and the ball plunger 8 can be released by relative movement in the tunnel axial direction. Therefore, even during or after connection, the connection can be released and the connection work can be redone.

[0037] In addition, instead of the ball plunger 8, the locking mechanism may use a pin plunger 81 (spring plunger) as shown in FIG. 6(a), in which a pin, which is a spring-biased locking member, is installed so as to protrude into the hollow portion 61.

[0038] When it is not necessary to release the lock, the locking mechanism may be such that a locking member is attached to a leaf spring 82, and the locking member is installed so as to protrude into the hollow portion 61 biased by the leaf spring 82, and locks the groove portion 51, as shown in Fig. 6(b). Furthermore, as shown in Fig. 6(c), a leaf spring 83 itself may be installed so as to protrude into the hollow portion 61, and an end of the leaf spring 83 may function as a locking member to lock the groove portion 51.

[0039] In addition, in this embodiment, the cross-sectional shapes of the hollow portion 61 of the connecting pin 5 and the boss portion 6 are both circular, but there are no limitations on the cross-sectional shape as long as the connecting pin 5 can be inserted into the hollow portion 61 of the boss portion 6. For example, the cross-sectional shape of the hollow portion 61 of the connecting pin 5 and the boss portion 6 may be elliptical or polygonal.

[0040] As described above, this embodiment is a joint structure of a steel support 1 formed by connecting a first support member 1a and a second support member 1b, which are divided into left and right halves, at their top ends, and is provided with a pair of connecting pins 5a, 5b attached to the top end of the first support member 1a facing the face side in the tunnel axis direction and attached to the top end of the second support member 1b facing the tunnel mouth side in the tunnel axis direction, and a pair of boss portions 6a, 6b attached to the top end of the first support member 1a so as to be insertable from the face side in the tunnel axis direction and attached to the top end of the second support member 1b so as to be insertable from the tunnel mouth side in the tunnel axis direction, into which the pair of connecting pins 5a, 5b are respectively inserted by relative movement between the first support member 1a and the second support member 1b in the tunnel axis direction, and the pair of boss portions 6a, 6b are each provided with a locking mechanism for locking the connecting pins 5a, 5b inserted in the boss portions 6a, 6b. With this configuration, the first support member 1a and the second support member 1b can be connected simply by moving the first support member 1a and the second support member 1b relative to each other so that the connecting pins 5a, 5b are inserted into the bosses 6a, 6b, so that errors during erection are tolerated and the first support member 1a and the second support member 1b can be easily connected. Therefore, it is possible to eliminate variations in the time required to erect the steel support 1 due to the skill of the worker.

[0041] Furthermore, in this embodiment, the connecting pin 5 is formed with a conical tapered surface 52 whose diameter becomes smaller toward the tip, and the hollow portion 61 of the boss portion 6 is formed with an annular tapered surface 62 whose diameter becomes larger toward the insertion opening. With this configuration, the tips of the connecting pins 5a, 5b are guided to the cylindrical portion where the locking mechanisms of the boss portions 6a, 6b are located by the annular tapered surface 62 of the boss portions 6a, 6b and the conical tapered surface 52. Therefore, any errors that may occur in positioning using a target and a total station or in positioning using motion capture technology with a marker and a camera can be tolerated.

[0042] Furthermore, in this embodiment, the locking mechanism is a locking member that is installed so as to protrude into the hollow portion 61 of the boss portion 6 by the force of a spring, and the connecting pin 5 is locked to the boss portion 6 by fitting the locking member into a groove portion 51 formed in the connecting pin 5. With this configuration, the connecting pin 5 can be securely locked to the boss portion 6.

[0043] Furthermore, in this embodiment, the locking member is a ball plunger 8. With this configuration, even during or after connection, the connection can be released and the connection work can be redone.

[0044] The present invention has been described above based on the embodiment. This embodiment is merely an example, and it will be understood by those skilled in the art that various modifications are possible in terms of the combination of the respective components, and that such modifications are also within the scope of the present invention. [Explanation of symbols]

[0045] 1 Steel shoring 1a 1st shoring member 1b 2nd shoring member 2, 2a, 2b Upper flange 3, 3a, 3b Lower flange 4a, 4b Web 5, 5a, 5b connecting pin 6, 6a, 6b Boss part 7a, 7b Support plate 8 Ball Plunger 9. Erector device 41a, 41b opening 51 Groove 52 Conical tapered surface 61 Hollow part 62 Annular tapered surface 71a, 71b extension surface 72a, 72b opening 73a, 73b Reinforcement plate 81 Pin Plunger 82, 83 Leaf spring 91 Boom 92 Clamp 93 Sub-boom

Claims

1. A joint structure of a steel support formed by connecting a first support member and a second support member divided into left and right parts at the top end, A pair of connecting pins are attached to the top end of the first support member toward the face side in the tunnel axis direction and to the top end of the second support member toward the portal side in the tunnel axis direction; a pair of boss portions attached to the top end of the first support member so as to be insertable from the tunnel face side in the tunnel axis direction, and attached to the top end of the second support member so as to be insertable from the tunnel mouth side in the tunnel axis direction, into which a pair of connecting pins are respectively inserted by relative movement between the first support member and the second support member in the tunnel axis direction; A joint structure for steel support, characterized in that a pair of boss portions each have a locking mechanism for locking the connecting pin inserted into the boss portion.

2. The connecting pin has a conical tapered surface having a diameter that decreases toward the tip, 2. The joint structure for a steel support according to claim 1, characterized in that the hollow portion of the boss portion is formed with an annular tapered surface whose diameter increases toward the insertion opening.

3. The joint structure of a steel support as described in claim 1 or 2, characterized in that the locking mechanism is a locking member installed so as to protrude into the hollow portion of the boss portion by the force of a spring, and the connecting pin is locked to the boss portion by fitting the locking member into a groove portion formed in the connecting pin.

4. 4. The joint structure for a steel support according to claim 3, wherein the locking member is a ball plunger.

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