JP7639542B2 - Steel shoring joint structure - Google Patents

Description

The present invention relates to a joint structure for steel supports.

When constructing tunnel supports using the New Austrian Tunneling Method (NATM) method, steel supports are made by bending steel materials called H-beams into the arch shape of the tunnel. The steel supports are made by connecting two support members on the left and right at the top center (top) to form an arch shape, which is then erected into the cross section of the tunnel.

The joint structure of steel support structures is generally such that joint plates attached to the top ends of the left and right support members are butted together and bolted together, and workers are required to enter just below the ground to connect the bolts.

A joint structure for steel support that avoids bolt fastening by workers has been proposed (see, for example, Patent Document 1). In Patent Document 1, a male joint plate with a male connector is provided at the top end of one support member, and a female joint plate with a female connector is provided at the top end of the other support member, and the abutment surfaces of the male joint plate and female joint plate are slid relative to each other in the width direction while in abutment with each other, whereby the male connector is engaged with the female connector.

JP 2018-178452 A

However, in conventional technology, the abutment surfaces of the male and female joint plates are in contact with each other and slid relative to each other, connecting the female and male connectors formed on each abutment surface. Therefore, the operator of the erector device that erects the steel support must accurately align the left and right sides while shifting the left and right support members back and forth, which requires skilled technique.

The present invention was made in consideration of these circumstances, and aims to provide a joint structure for steel shoring that can resolve the above-mentioned problems and easily connect the left and right shoring members.

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 provided 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.

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, which allows for errors during erection and provides the effect of easily connecting the first support member and the second support member.

1 is a perspective view showing a configuration of a first embodiment of a steel support according to the present invention. FIG. FIG. 2 is an enlarged perspective view showing the configuration of a joint structure of the steel support shown in FIG. 1 . FIG. 2 is a cross-sectional view showing the configuration of a joint structure of the steel support shown in FIG. 1 . FIG. 2 is a diagram showing an example of the configuration of an erector device for erecting the steel support shown in FIG. 4 is an explanatory diagram illustrating a coupling operation of the joint structure shown in FIG. 3 . FIG. 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 .

Next, a form for implementing the present invention (hereinafter simply referred to as "embodiment") will be specifically described with reference to the drawings.

Referring to FIG. 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 located on the right side toward the tunnel face and a second support member 1b located on the left side toward the tunnel face, and the top ends (upper central parts) are connected to form an arch shape.

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

Referring to Figures 2 and 3, this joint structure comprises a connecting pin 5a and a boss portion 6a attached to the top end of the first support member 1a, and a connecting pin 5b and a boss portion 6b attached to the top end of the second support member 1b. The connecting pin 5b of the second support member 1b is inserted into the boss portion 6a of the first support member 1a, and the connecting pin 5a of the first support member 1a is inserted into the boss portion 6b of the second support member 1b, and the two are engaged to connect the first support member 1a and the second support member 1b. Note that Figure 2 is an enlarged view of the top end. Also, Figure 3 is a cross-sectional view cut along a plane passing through the axes of the boss portions 6a, 6b and the connecting pins 5a, 5b.

The H-shaped steel that constitutes 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.

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 mouth end of the upper flange 2a and the lower flange 3a and fixed by welding or the like. The reference number 73a in FIG. 3 is a reinforcing plate that reinforces the fixation of the support plate 7a.

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, facing the face side and parallel to the upper flange 2a and lower flange 3a (in the tunnel axis direction).

The web 4a and support plate 7a at the top end of the first support member 1a are formed with an opening 41a and an opening 72a, respectively, through which the boss portion 6a passes. The boss portion 6a passes through the opening 41a and the opening 72a, and is fixed to the web 4a and 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.

The H-shaped steel that constitutes 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 in 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.

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 number 73b in FIG. 3 is a reinforcing plate that reinforces the fixation of the support plate 7b.

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 the tunnel mouth side and parallel to the upper flange 2b and lower flange 3b (in the tunnel axis direction).

The web 4b and support plate 7b at the top end of the second support member 1b are formed with openings 41b and 72b, respectively, through which the boss portion 6b passes. The boss portion 6b passes through the openings 41b and 72b, and the hollow portion 61 is fixed to the web 4b and 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, parallel to the upper flange 2b and lower flange 3b (in the tunnel axis direction).

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

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 a predetermined interval in the circumferential direction, and a tip portion that has a conical tapered surface 52 whose diameter decreases as it approaches the tip. There is no particular limit to the number of rows of grooves 51, and it may be one or two rows, or four or more rows.

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

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

When the connecting pin 5 is inserted, the ball of the ball plunger 8 comes into contact with the peripheral surface of the connecting pin 5 while being biased by a spring, so the ball plunger 8 also functions as a guide mechanism. Note that if multiple 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 guidance.

The erector device 9 shown in Figure 4 is used to erect the steel support 1. The erector device 9 is composed of 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.

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. When the sub-booms 93 are provided, they are used when erecting a large steel support 1 in a relatively large tunnel.

The first support member 1a and the second support member 1b are gripped by clamps 92 attached to each of a pair of booms 91 (sub-booms 93), and connected to form an arch shape, so that the steel support 1 is erected at a designated position inside the tunnel.

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.

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 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.

As a result, 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 by the annular tapered surface 62 and the conical tapered surface 52 of the boss portion 6 to the cylindrical portion where the ball plunger 8 of the boss portion 6 is located, as shown in FIG. 5(a). Therefore, errors in positioning using a target and a total station, or positioning using motion capture technology with a marker and a camera, can be tolerated.

Then, as shown in FIG. 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 relative to each other in the tunnel axis 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 ground to join the two bolts.

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 it during insertion and to confirm the connection.

In this embodiment, the locking mechanism is made up of the groove 51 of the connecting pin 5 and the ball plunger 8, so 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.

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.

When there is no need to release the lock, the locking mechanism may be such that a locking member is attached to the leaf spring 82 and the locking member is installed so as to protrude into the hollow portion 61 biased by the leaf spring 82, as shown in FIG. 6(b), and locks the groove portion 51 with the locking member. Furthermore, as shown in FIG. 6(c), the leaf spring 83 itself may be installed so as to protrude into the hollow portion 61, and the end of the leaf spring 83 may act as a locking member to lock the groove portion 51.

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 shapes of the hollow portion 61 of the connecting pin 5 and the boss portion 6 may be elliptical or polygonal.

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.

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 portions in which the locking mechanisms of the boss portions 6a, 6b are disposed by the annular tapered surfaces 62 of the boss portions 6a, 6b and the conical tapered surfaces 52. 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.

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 .

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.

The present invention has been described above based on an 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 each component, and that such modifications are also within the scope of the present invention.

Reference Signs List 1 Steel support 1a First support member 1b Second support member 2, 2a, 2b Upper flange 3, 3a, 3b Lower flange 4a, 4b Web 5, 5a, 5b Connecting pin 6, 6a, 6b Boss portion 7a, 7b Support plate 8 Ball plunger 9 Erector device 41a, 41b Opening 51 Groove portion 52 Conical tapered surface 61 Hollow portion 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 (4)

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 axial direction and to the top end of the second support member toward the portal side in the tunnel axial 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. The connecting pin has a conical tapered surface whose diameter 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. The joint structure for steel support according to 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 bias 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. The joint structure for steel supports according to claim 3, characterized in that the locking member is a ball plunger.

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