Shoring unit and shoring assembly method

Abstract

To provide: a shoring unit which comprises a tie member and steel shoring and can improve both workability and safety during shoring construction; and a shoring assembly method based on the shoring unit.SOLUTION: A shoring unit 3 comprises: steel shoring 4 formed from a pair of flanges 41, 41 and a web 42 laterally spanning between the pair of flanges 41, 41; a tie member 5 fixed to a pit mouth side surface of the web 42; a mounting member 7 provided at a pit mouth end of the tie member 5; and a receiving member 6 that is engageable with a mounting member 7 and laterally spans between excavation face ends of the pair of flanges 41, 41 at a position corresponding to the tie member 5.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a shoring unit and a shoring assembly method using the shoring unit. [Background technology]

[0002] In tunnel construction using NATM, the ground surface exposed by tunnel excavation is sealed off early 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 normal to the tunnel from inside.

[0003] When assembling steel shoring, it is common to use heavy machinery such as an erector to hold the steel shoring, place the left and right steel shoring near the top of the face, and then manually tighten the bolts. However, tightening bolts manually is time-consuming and requires that the work be done on the exposed ground before the shoring is completed, or directly under the first shotcrete.

[0004] For this reason, construction methods aimed at improving workability and safety during construction of shoring have been disclosed.For example, Patent Document 1 discloses a tunnel construction method in which a male connector is provided at an end (joint) of one of a pair of left and right steel shoring, and a female connector is formed at an end (joint) of the other steel shoring, and an erector device having a pair of hands capable of holding the steel shoring is used to butt the joints of the left and right steel shoring together to engage the male connector with the female connector, and then the steel shoring assembled in an arch shape is erected along the face of the tunnel.

[0005] The steel shoring must be connected to the existing steel shoring (the shoring adjacent to the tunnel mouth side) via tie materials to prevent it from falling over. Generally, the sheath tube method and the tie rod method are used for such tie materials. The sheath tube method connects the front and rear steel shoring by inserting a hook formed at the tip of a tie material made of a steel rod into a sheath tube fixed to the steel shoring (see Patent Document 2, for example). The tie rod is installed horizontally between the steel shoring as a tie material, and a nut is fastened to the end of the tie rod that passes through the web of the steel shoring. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 6374051 [Patent Document 2] Patent Publication No. 2021-67136 Summary of the Invention [Problem to be solved by the invention]

[0007] The work of installing ties is generally done manually between new and existing steel supports. Therefore, even if the tunnel construction method described in Patent Document 1 is adopted, workers must enter the exposed ground before the shoring is completed or directly under the primary shotcrete to install the ties. Furthermore, installing ties manually is time-consuming.

[0008] The present invention aims to propose a shoring unit comprising connecting materials and steel shoring, which makes it possible to improve workability and safety during shoring construction, and to propose a shoring assembly method using this shoring unit. [Means for solving the problem]

[0009] The support unit of the present invention, which solves such problems, comprises a steel support consisting of a pair of flanges and a web suspended across the pair of flanges, ties fixed to the tunnel mouth side of the webs, mounting members provided at the tunnel mouth side ends of the ties, and receiving members engageable with the mounting members suspended across the face side ends of the pair of flanges at positions corresponding to the ties. The mounting members comprise a sliding portion that slides the receiving member, and a storage portion that stores the receiving member. The storage portion has an opening that opens in a direction intersecting with the receiving member, and the sliding portion is inclined so as to approach the opening as it moves from the tunnel mouth side to the face side.

[0010] The shoring assembly method of the present invention also includes an erection step of erecting the shoring unit near the face, and a connection step of connecting the shoring unit to another shoring unit provided on the tunnel mouth side via the tie material. In the connection step, the shoring unit is pulled toward the other shoring unit, and the mounting members of the shoring unit are engaged with the receiving members of the other shoring unit.

[0011] According to this shoring unit and shoring assembly method, the tie members can be easily connected to the existing steel shoring (existing shoring unit) simply by engaging the mounting members with the receiving members. Therefore, even when assembling the steel shoring using heavy machinery, workers do not need to enter the exposed ground before the shoring is completed or directly under the primary shotcrete in order to install the tie members.

[0012] In addition, when the mounting member includes a fixed plate fixed to the end of the connecting material, a guide plate provided on the wellhead side of the fixed plate with a gap therebetween, and a connecting member connecting the fixed plate and the guide plate, the receiving member is a steel rod that can be inserted into the gap. In this case, it is preferable that the fixed plate has a width larger than that of the guide plate, and the guide plate has a shape in which the width narrows toward the wellhead side. In addition, it is preferable that the connecting member is a steel rod arranged across the fixed plate and the guide plate. Furthermore, when the connecting material is a steel pipe with a pair of slits formed at the wellhead end, the fixed plate may be welded to the connecting material while being inserted into the pair of slits.

[0013] In this way, when the shoring unit is pulled toward the tunnel mouth and the guide plate comes into contact with the support member, the tip of the guide plate slides on the support member and the connecting material bends in a direction that intersects with the support member. Then, when the face side end of the guide plate is pushed closer to the tunnel mouth than the support member, the connecting material returns to its original state and the support member enters the gap between the guide plate and the fixed plate, and the mounting member and the support member are engaged. Therefore, it is possible to connect shoring units to each other just by pulling the shoring unit toward the existing shoring unit. Effect of the Invention

[0014] According to the shoring unit of the present invention and the shoring assembly method using the same, it is possible to improve workability and safety during shoring construction. [Brief description of the drawings]

[0015] [Figure 1] 1A and 1B are diagrams showing an overview of a tunnel according to an embodiment of the present invention, in which (a) is a cross-sectional view and (b) is a longitudinal section view. [Diagram 2] FIG. 2 is a diagram showing a support unit of the first embodiment, in which (a) is a cross-sectional view and (b) is a cross-sectional view viewed from a direction perpendicular to (a). [Diagram 3]FIG. [Figure 4] FIG. 1 shows a connecting member, where (a) is a front view seen from the face side, (b) is a plan view, (c) is a side view, and (d) is a front view seen from the tunnel mouth side. [Diagram 5] 4(a) to 4(e) are diagrams showing a connecting process of the support assembling method of the first embodiment. [Figure 6] A cross-sectional view showing a support unit of a second embodiment. [Figure 7] FIG. 1 shows a connecting member, where (a) is a front view seen from the face side, (b) is a plan view, (c) is a side view, and (d) is a front view seen from the tunnel mouth side. [Figure 8] 1(a) and 1(b) are cross-sectional views showing examples of the receiving member. [Figure 9] 6(a) to 6(c) are diagrams showing a connecting process of the support assembling method of the second embodiment. [Figure 10] 4A and 4B are diagrams showing an engagement state between the mounting member and the receiving member, in which (a) is a cross-sectional view and (b) is a front view seen from the inner space side. [Figure 11] 11A to 11C are cross-sectional views showing examples of states in which the mounting member and the receiving member are engaged, and (d) to (f) show the positional relationship between the visual identification marks and the visual identification plates corresponding to (a) to (c). [Figure 12] FIG. 11 is a diagram showing an example of a state in which the mounting member and the receiving member are not engaged, where (a) and (c) are cross-sectional views, and (d) to (f) show the positional relationship between the visual identification mark and the visual identification plate corresponding to (a) to (c). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] First Embodiment In the first embodiment, a case where a tunnel is constructed by NATM will be described. As shown in Fig. 1(a) and (b), a tunnel T is stabilized by blocking the exposed natural ground surface Gs by excavating the natural ground G with supports 1 made of sprayed concrete 2 and steel supports 4. In addition, auxiliary construction methods such as forepoling (short-length pre-supporting work), head bolt work, and leg reinforcement work may be used in combination during tunnel construction as necessary.

[0017] In tunnel construction, first, the natural ground G is excavated to form a borehole (tunnel T). The excavation method for the tunnel T is not limited, and may be, for example, blasting excavation or mechanical excavation. The excavation length of the tunnel T per cycle is determined according to the natural ground conditions (natural ground grade, earth covering, etc.), but in this embodiment, it is 1.0 to 1.2 m.

[0018] After the tunnel T has been excavated to a predetermined length (1.0 to 1.2 m in this embodiment), the ground G is excavated and the support 1 is formed along the ground surface Gs exposed. As shown in Fig. 1(b) , the support 1 in this embodiment includes shotcrete 2 consisting of primary shotcrete 21 and secondary shotcrete 22, and a support unit 3. The construction of the support 1 includes primary spraying work, erection work, and secondary spraying work (spraying work).

[0019] In the primary spraying work, primary shotcrete 21 is sprayed onto the natural ground surface Gs exposed by excavation of the natural ground G. The primary shotcrete 21 is sprayed onto the wall surface (side surface) of the tunnel T as well as the face K. The spraying thickness of the primary shotcrete 21 may be determined appropriately, and may be, for example, 5 cm.

[0020] In the erection work, a shoring unit 3 is erected near the face K. The shoring unit 3 comprises a steel shoring 4, a connecting member 5, and a receiving member 6. In the erection work, a pair of left and right steel shoring 4, 4 are connected at the top to form an arch shape. When erecting the shoring unit 3, an installation process, an erection process, and a connection process are performed.

[0021] In the installation process, as shown in Fig. 2, a tie material 5 is attached to a steel support 4 to form a support unit 3. As shown in Fig. 3, the steel support 4 is formed by processing a so-called H-shaped steel consisting of a pair of flanges 41, 41 and a web 42 horizontally disposed across the pair of flanges 41, 41. In the steel support 4, receiving members 6 are welded to the flanges 41, 41 corresponding to the attachment points of the tie material 5, and bolt insertion holes 43 are formed in the web 42.

[0022] The tie member 5 is a member that connects the steel supports 4 arranged at the front and rear (see FIG. 1(b)). In this embodiment, the tie member 5 is fixed with its tip (the end on the face K side) abutting against the web 42 of the steel support 4. The tie member 5 is fixed to the side of the portal of the web 42. As shown in FIG. 4(a), the tie member 5 is made of a square steel pipe with a rectangular cross section, and a nut 51 is welded to the inner hollow portion of the tip of the tie member 5. As shown in FIGS. 2(a) and (b), the tie member 5 is fixed to the steel support 4 by fastening the nut 51 to a bolt 52 that passes through the web 42.

[0023] An attachment member 7 is provided at the base end (the end on the wellhead side) of the tether 5. As shown in Figures 4(b) and (c), the attachment member 7 includes a fixed plate 71 fixed to the end of the tether 5, a guide plate 72 provided on the wellhead side of the fixed plate 71 with a gap therebetween, and a connecting member 73 connecting the fixed plate 71 and the guide plate 72.

[0024] As shown in Fig. 4(c), the fixing plate 71 is made of a rectangular steel plate having a width greater than that of the guide plate 72. A pair of slits into which the fixing plate 71 can be inserted is formed in the end face of the square steel pipe at the base end of the connecting material 5. The pair of slits are formed along the axial direction of the connecting material 5 at positions facing each other across the central axis of the connecting material 5. The fixing plate 71 is fixed (welded) to the connecting material 5 while being inserted into the slits. The plate surface of the fixing plate 71 is parallel to the axis of the connecting material 5, and the long side (width direction) is perpendicular to the axis of the connecting material 5.

[0025] The guide plate (sliding portion) 72 has a gap (accommodating portion) between it and the fixed plate 71 that can accommodate the receiving member 6. Both ends (top and bottom ends in FIG. 4(c)) of the gap (accommodating portion) are open (opening). The guide plate 72 is made of a triangular steel plate that narrows in width toward the wellhead. In other words, the end of the guide plate 72 on the wellhead side is inclined. The shape of the guide plate 72 is not limited as long as the end on the wellhead side is inclined so as to approach the opening of the gap as it approaches the face side. The guide plate 72 and the fixed plate 71 are arranged so that their plate surfaces are parallel to the flange 41.

[0026] The connecting member 73 is a steel rod disposed across the fixed plate 71 and the guide plate 72. In this embodiment, a pair of connecting members 73, 73 are welded to the fixed plate 71 and the guide plate 72 with the fixed plate 71 and the guide plate 72 sandwiched between them.

[0027] 2(a) and (b), the receiving member 6 is horizontally disposed on the face side ends of the pair of flanges 41, 41 at a position corresponding to the connecting member 5. The receiving member 6 is a steel rod that can be inserted into the gap between the fixed plate 71 and the guide plate 72, and is welded to the end faces of the pair of flanges 41, 41 as shown in FIG.

[0028] The ties 5 are attached to the steel supports 4 by first disposing the ties 5 on the face K side of the webs 42 of the steel supports 4 and inserting bolts 52 into the bolt insertion holes 43 formed in the webs 42. The ties 5 are then attached to the steel supports 34 by screwing the bolts 52 into the nuts 51.

[0029] In the erection process, the steel supports 4 to which the connecting materials 5 are fixed are erected near the face K along the surface of the primary shotcrete 21 (or the ground surface Gs). At this time, as shown in FIG. 1(a), a pair of left and right steel supports 4, 4 are assembled in an arch shape by connecting them at their tops.

[0030] In the connection process, as shown in Fig. 5, a tie member 5 fixed to a steel support (new steel support) 4 is connected to an existing steel support 4a installed on the tunnel mouth side. The tie member 5 is connected to the existing steel support 4a by engaging an attachment member 7 with a receiving member 6 fixed to the existing steel support 4a.

[0031] In the connecting process, as shown in Figures 5(a) and (b), first, the steel support (new steel support) 4 is pulled toward the existing steel support 4a, and the guide plate 72 is brought into contact with the support member 6. Then, when the steel support 4 is pulled toward the existing steel support 4a with the guide plate 72 in contact with the support member 6, the tip of the guide plate 72 slides on the support member 6 and bends (is pushed up) in a direction intersecting with the support member 6, which is the short side direction of the connecting material 5, as shown in Figures 5(c) and (d). At this time, the guide plate 72 is inserted into the space surrounded by the pair of flanges 41, 41 and the web 42 of the existing steel support 4a. Then, when the face side end of the guide plate 72 is pushed in closer to the mine mouth than the receiving member 6, the receiving member 6 comes into contact with the fixed plate 71, and then as shown in Figure 5(e), the receiving member 6 enters the gap (accommodation section) between the guide plate 72 and the fixed plate 71, the tying material 5 returns to its original state (lowers), and the mounting member 7 and the receiving member 6 are engaged. Note that since the width of the fixed plate 71 is larger (wider) than the width of the guide plate 72, when the guide plate 72 is pushed in closer to the mine mouth than the receiving member 6, the fixed plate 71 is not pushed in closer to the mine mouth than the receiving member 6.

[0032] After the steel support 4 is connected to the existing steel support 4a by the connecting material 5, the secondary shotcrete 22 is sprayed toward the side of the tunnel T (see FIG. 1(b)).

[0033] According to the shoring unit 3 and shoring assembly method of this embodiment, the tie material 5 can be easily connected to the existing steel shoring 3a (existing shoring unit 3) simply by engaging the mounting member 7 with the receiving member 6. Therefore, even when the steel shoring 4 is assembled using heavy machinery, there is no need for workers to enter the exposed ground before the shoring is completed or directly under the primary shotcrete 21 in order to install the tie material 5.

[0034] Furthermore, the support unit 3 has a simple structure and is constructed by combining relatively easily available parts, so that manufacturing costs can be kept low. Since the guide plate 72 is plate-shaped, it is easy to get between the flanges 41 of the existing steel support 4a, and the guide plate 72 is unlikely to come into contact with the existing steel support 4a. Therefore, damage to the connecting material 5 when connecting it to the existing steel support 4a can be suppressed.

[0035] Second Embodiment In the second embodiment, a case where a tunnel is constructed by NATM will be described as the same as in the first embodiment. The tunnel T is stabilized by blocking the exposed natural ground surface Gs by excavating the natural ground G with supports 1 made of sprayed concrete 2, steel supports 4, etc. (see FIG. 1).

[0036] In tunnel construction, first, the natural ground G is excavated to form a borehole (tunnel T). The excavation method for the tunnel T is not limited, and may be, for example, blasting excavation or mechanical excavation. The excavation length of the tunnel T per cycle is determined according to the natural ground conditions (natural ground grade, earth covering, etc.), but in this embodiment, it is 1.0 to 1.2 m.

[0037] After the tunnel T has been excavated to a predetermined length (1.0 to 1.2 m in this embodiment), the ground G is excavated and the support 1 is formed along the ground surface Gs exposed. The support 1 in this embodiment includes a shotcrete 2 consisting of a primary shotcrete 21 and a secondary shotcrete 22, and a support unit 3 (see FIG. 1(b)). The construction of the support 1 includes a primary shotcrete work, an erection work, and a secondary shotcrete work (spraying work).

[0038] In the primary spraying work, primary shotcrete 21 is sprayed onto the ground surface Gs exposed by excavation of the ground G. In the erection work, the shoring unit 3 is erected in the vicinity of the face K. When erecting the shoring unit 3, an attachment process, an erection process, and a connection process are performed.

[0039] In the installation process, as shown in FIG. 6, the tie material 5 is attached to the steel shoring 4 to form the shoring unit 3. The steel shoring 4 has a receiving member 6 welded to it in advance at the factory. The tie material 5 is a member that connects the steel shoring 4 arranged at the front and rear (see FIG. 1(b)). The tie material 5 in this embodiment is fixed with its tip (the end on the face K side) abutting against the web 42 of the steel shoring 4. The tie material 5 is fixed to the side of the portal of the web 42. The tie material 5 is made of a steel pipe, and a nut 51 is welded to the inner hollow part of the tip of the tie material 5 as shown in FIG. 7(a). The tie material 5 is fixed to the steel shoring 4 by fastening the nut 51 to the bolt 52 passing through the web 42.

[0040] 7(b) to (d), a mounting member 9 is provided at the base end (the end on the wellhead side) of the connecting material 5. The mounting member 9 has a base portion 91 that is rectangular in plan view and a locking portion 92 that is triangular in plan view, and is formed by bending a steel plate that is shaped like an arrow in plan view into an inverted V shape.

[0041] The mounting member 9 is fixed to the tie member 5 by welding the inner surface of the base 91 to the base end of the tie member 5. A part of the base 91 protrudes from the base end face of the tie member 5 toward the mine mouth side, and a gap (accommodation section) capable of accommodating the receiving member 6 is formed between the base end face of the tie member 5 and the locking section 92. In addition, the length of the locking section 92 is such that the tip of the locking section 92 abuts on the web 42 of the steel support 4 to be joined.

[0042] The locking portion 92 has a width greater than that of the base 91, and has an inclined triangular (trapezoidal) shape with the sides narrowing toward the wellhead. That is, the end of the locking portion 92 on the base 91 side (connector 5 side) protrudes beyond the base 91. The length of protrusion of the locking portion 92 from the base 91 is approximately the same as the diameter (width) of the connector 5.

[0043] As shown in Fig. 6, the receiving member 6 is horizontally installed on the face side end of the pair of flanges 41, 41 at a position corresponding to the connecting member 5. The receiving member 6 is a straight steel rod that can be inserted into the gap between the connecting member 5 and the locking portion 92, and both ends are welded to the flanges 41, 41. When the flange spacing is large, as shown in Fig. 8(a), both ends can be bent and welded to the flanges to increase the degree of end fixation, so that a steel rod of a common diameter can be used. Also, as shown in Figs. 8(a) and (b), by making the dimension from the web 42 to the receiving member 6 constant regardless of the size of the steel support 4, a common connecting member can be used.

[0044] In addition, as shown in Figs. 7(b) to (d), a visual confirmation plate 53 is attached to the base end (the end on the wellhead side) of the connecting material 5 in this embodiment. The visual confirmation plate 53 is provided with an attachment portion 53a and a visual confirmation portion 53b by bending a metal plate into an L-shape. The attachment portion 53a is attached to the inner space side of the connecting material 5 and is fixed to the connecting material 5 via a screw 53c. The visual confirmation portion 53b protrudes laterally (toward the inner space) from the attachment portion 53a and is parallel to the web 42 of the steel support 4. In addition, the visual confirmation portion 53b has a length that protrudes toward the inner space side beyond the steel support 4 (flange 41). Furthermore, the surface of the visual confirmation portion 53b is colored in a color (e.g., white) that is easy for the operator to confirm.

[0045] The ties 5 are attached to the steel supports 4 by first disposing the ties 5 on the face K side of the webs 42 of the steel supports 4 and inserting bolts 52 into the bolt insertion holes 43 formed in the webs 42. The ties 5 are then attached to the steel supports 34 by screwing the bolts 52 into the nuts 51.

[0046] In the erection process, the steel supports 4 to which the connecting members 5 are fixed are erected near the face K along the surface of the primary shotcrete 21 (or the ground surface Gs). At this time, the pair of left and right steel supports 4, 4 are assembled in an arch shape by connecting them at their tops (see FIG. 1(a)).

[0047] In the connecting process, as shown in Fig. 9, the connecting material 5 fixed to the steel support (new steel support) 4 is connected to the existing steel support 4a installed on the tunnel mouth side. The connecting material 5 is connected to the existing steel support 4a by engaging the mounting member 9 with the receiving member 6 fixed to the existing steel support 4a.

[0048] In the connecting process, as shown in Fig. 9(a) and (b), first, the steel support (new steel support) 4 is pulled toward the existing steel support 4a, and the mounting member 9 is brought into contact with the receiving member 6. Then, when the steel support 4 is pulled toward the existing steel support 4a with the mounting member 9 in contact with the receiving member 6, as shown in Fig. 9(b), the two V-shaped locking portions 92 (inclined portions on the sides) at the tip of the mounting member 9 slide on the receiving member 6 as sliding portions, and the connecting material 5 bends (is pushed up) in the cross direction without sliding toward the receiving member 6. At this time, the mounting member 9 is inserted into the space surrounded by the pair of flanges 41, 41 and the web 42 of the existing steel support 4a. Then, when the face side end of the engaging portion 92 is pushed closer to the tunnel mouth than the receiving member 6, as shown in Figure 9(c), the tip of the engaging portion 92 hits the web 42 of the existing steel support 4a and the receiving member 6 enters the gap (accommodation portion) between the end face of the connecting member 5 and the engaging portion 92 of the mounting member 9, causing the connecting member 5 to return to its original state (lower) and the mounting member 9 and the receiving member 6 to become engaged.

[0049] Fig. 10 shows the engagement state between the mounting member 9 and the receiving member 6. As shown in Fig. 10(b), a visual identification mark 45 is provided on the flange 41 of the existing steel support 4a at a position corresponding to the visual identification plate 53. The visual identification mark 45 is in a color (e.g., white) that is easy for an operator to see, and has, for example, a triangular shape. The visual identification mark 45 is provided on the flange 41 by drawing it on the flange 41 or by attaching a sticker thereon.

[0050] 11 and 12 are explanatory diagrams showing an example of a method for checking the engagement state based on the positional relationship between the tip of the visual identification mark 45 and the visual identification plate 53. The operator visually checks the visual identification mark 45 from the tunnel mouth side (direction E in FIG. 10(a)) of the existing steel support 4a, and checks that the mounting member 9 and the receiving member 6 are engaged based on the positional relationship between the tip of the visual identification mark 45 and the visual identification plate 53. That is, when it is confirmed that the tip of the visual identification mark 45 overlaps with the visual identification plate 53 as shown in FIGS. 11(d) to (f), it is determined that the mounting member 9 and the receiving member 6 are engaged as shown in FIGS. 11(a) to (c). The width dimension of the visual identification plate 53 is set to a size that allows the operator to determine that they are engaged.

[0051] On the other hand, as shown in FIG. 12(a), when the mounting member 9 is not engaged with the receiving member 6 and is placed on the receiving member 6, the tip of the visual identification mark 45 is located below the visual identification plate 53 as shown in FIG. 12(d). When the mounting member 9 is located below the receiving member 6 as shown in FIG. 12(b), the tip of the visual identification mark 45 is located above the visual identification plate 53 as shown in FIG. 12(e). In this way, when the tip of the visual identification mark 45 is off the visual identification plate 53, the operator determines that the mounting member 9 and the receiving member 6 are not engaged. Furthermore, when the tip of the visual identification plate 53 is away from the end face of the flange 41 (the tip of the visual identification mark 45) as shown in FIG. 12(f), the mounting member 9 is located on the face side of the receiving member 6 as shown in FIG. 12(c), and is not engaged, so the operator determines that the mounting member 9 and the receiving member 6 are not engaged.

[0052] After the steel support 4 is connected to the existing steel support 4a by the connecting material 5, the secondary shotcrete 22 is sprayed toward the side of the tunnel T (see FIG. 1(b)).

[0053] According to the shoring unit 3 and the shoring assembly method of the second embodiment, the same effects as those of the shoring unit 3 and the shoring assembly method of the first embodiment can be obtained. Furthermore, since the mounting member 9 can be easily formed by cutting a steel plate, it is easy to manufacture and low cost.

[0054] The embodiment of the present invention has been described above. However, the present invention is not limited to the above embodiment, and each of the above components can be appropriately modified without departing from the spirit of the present invention.

[0055] For example, the method of fixing the connecting material 5 and the mounting members 7, 9 is not limited to welding, and may be fixed via a jig, for example. Also, the slits in the connecting material 5 may be formed as necessary (according to the fixing method of the mounting members 7, 9). [Explanation of symbols]

[0056] 1 Shoring 2. Shotcrete 3 Shoring Unit 4 Steel shoring 41 Flange 42 Web 43 Bolt insertion hole 45 Visibility Mark 5. Connectors 51 Nut 52 Volts 53 Visibility Plate 6 Receiving member 7 Mounting material 71 Fixing plate 72 Guide plate 73 Connecting members 9 Mounting material 91 Base 92 Locking part T-Tunnel

Claims

1. A steel support structure including a pair of flanges and a web horizontally disposed on the pair of flanges; A tie fixed to the wellhead side of the web; An attachment member provided at the wellhead side end of the connecting material; A support unit including a receiving member that can be engaged with the mounting member that is horizontally supported on the face side end of the pair of flanges at a position corresponding to the connecting member, The mounting member includes a sliding portion that slides on the receiving member and an accommodating portion that accommodates the receiving member, The housing portion has an opening portion that opens in a direction intersecting with the receiving member, A support unit characterized in that the sliding portion is inclined so as to approach the opening as it moves from the tunnel mouth side to the face side.

2. The mounting member includes a fixed plate fixed to an end of the connecting material, a guide plate provided on the hole mouth side of the fixed plate with a gap therebetween, and a connecting member connecting the fixed plate and the guide plate, The receiving member is a steel rod that can be inserted into the gap, The fixing plate has a width greater than that of the guide plate, The support unit according to claim 1, characterized in that the guide plate has a shape in which its width narrows toward the tunnel mouth side.

3. The support unit according to claim 2 , characterized in that the connecting member is a steel rod arranged across the fixed plate and the guide plate.

4. The connecting material is made of a steel pipe having a pair of slits formed at the wellhead end, The support unit according to claim 2 , characterized in that the fixing plate is inserted into the pair of slits and welded to the connecting material.

5. The mounting member is formed by bending a steel plate formed in an arrow shape in a plan view, which has a base portion having a rectangular shape in a plan view and a locking portion having a generally triangular shape in a plan view, into an inverted V shape, and is fixed to the connecting material by welding an inner surface of the base portion to a base end portion of the connecting material, A part of the base protrudes from the base end surface of the connecting material toward the wellhead, and the receiving portion is formed between the base end surface of the connecting material and the locking portion, and the receiving portion is capable of receiving the receiving member. The support unit according to claim 1 , characterized in that the engaging portion has the sliding portion at an end portion on the tunnel mouth side.

6. Further comprising a sight plate secured to the wellhead end of the tie, A visual identification mark is provided at a position corresponding to the visual identification plate on the inner hollow side flange of the steel support, The support unit according to claim 1 , characterized in that the sight plate has a surface parallel to the web and has a length that extends inward beyond the flange.

7. An erection process of erecting the shoring unit according to any one of claims 1 to 6 in the vicinity of a face; A connection process for connecting the shoring unit to another shoring unit provided on the tunnel mouth side via the connecting material, A support assembly method characterized in that, in the connecting process, the support unit is pulled toward the other support unit and the mounting member of the support unit is engaged with the receiving member of the other support unit.

Images