Supporting construction method, supporting unit, and supporting leg position correction device

Abstract

To propose a supporting construction method, a supporting unit, and a supporting leg position correction device that improve workability by preventing workers from entering a risk area of face collapse near a face while supporting construction.SOLUTION: A supporting assembly method includes an erection step of erecting a new steel supporting 3 to which weight-bearing ties 4 and horizontal ties 5 are attached near a face, a connection step of connecting the weight-bearing ties 4 and horizontal ties 5 to an existing steel supporting 30 provided on a tunnel mouth side of the new steel supporting 3, and a leg position correction step of correcting a position of legs of the new steel supporting 3 with a width adjustment rod 82. In the connection step, there are performed an operation of engaging a locking member 42 of the weight-bearing ties 4 with a first support member 61 of the existing steel supporting 30 and an operation of pulling the new steel supporting 3 toward the existing steel supporting 30 and attaching a connecting member 52 of the horizontal ties 5 to a second support member 62 of the existing steel supporting 30.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a support erection method, a support unit, and a support leg position correction device in tunnel construction. [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 erect the steel shoring, which is brought in lying on its side near the face, at a position with a specified distance on the face side of the existing steel shoring. For example, Patent Document 1 discloses a tunnel construction method in which the steel shoring is erected using heavy machinery equipped with an erector device with a hand that can grasp the steel shoring. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6374051 Summary of the Invention [Problem to be solved by the invention]

[0005] Positioning the steel support when erecting it requires surveying at a position away from the face and operating heavy machinery at the same time, which is time-consuming work. In addition, the legs of the erected arch-shaped steel support tend to spread out to the sides due to their own weight, but workers must avoid entering the area near the face where there is a risk of skin falling.

[0006] The present invention aims to propose a shoring construction method, a shoring unit, and a shoring leg position correction device that enable improved workability during shoring construction without workers entering the risk of skin falling areas near the face. [Means for solving the problem]

[0007] The shoring assembly method of the present invention, which solves such problems, includes an erection step of erecting a new steel shoring to which a weight-bearing tie member and a horizontal tie member are attached near the face, a connection step of connecting the weight-bearing tie member and the horizontal tie member to an existing steel shoring provided on the tunnel mouth side of the new steel shoring, and a leg position correction step of correcting the position of the leg of the new steel shoring by using a width adjustment bar. The weight-bearing tie member includes a horizontal member (horizontal member) whose base end is fixed to the new steel shoring so that the horizontal or tip end is higher than the base end, a locking member formed at the tip of the horizontal member, and a diagonal member whose tip end is fixed to the tip end of the horizontal member and whose base end is fixed to the new steel shoring above the horizontal member. Also, a connecting member is formed at the tip of the horizontal tie member. Furthermore, the existing steel support is formed with a first support member to which the locking member of the weight-bearing connecting material can be locked, and a second support member to which the connecting member can be attached. The connecting step involves the work of locking the locking member to the first support member, and the work of pulling the new steel support toward the existing steel support and attaching the connecting member to the second support member. The leg position correction step involves the work of inserting the tip of the width adjustment rod into a space surrounded by the flange and web of the leg of the new steel support, abutting the width adjustment rod against the existing steel support, and rotating the width adjustment rod around the abutment point with the existing steel support as a fulcrum to correct the position of the leg of the new steel support.

[0008] According to this shoring assembly method, it is possible to easily connect a new steel shoring to an existing steel shoring using weight-bearing ties and horizontal ties. Also, since there is no need to tighten the bolts manually, the steel shoring can be connected using an erector device having a pair of hands that can hold the steel shoring, and manual work on the exposed ground before the shoring is completed or directly under the primary shotcrete can be omitted.

[0009] The weight-bearing connecting material transfers the weight of the newly constructed steel support to the existing steel support, ensuring the stability of the newly constructed steel support before the base is consolidated. Furthermore, the width adjustment bar makes it possible to correct the position of the legs of newly constructed arch-shaped steel supports, whose legs have spread out due to their own weight, without workers entering the area near the face where the skin may fall.

[0010] In the leg position correction process, it is desirable to further carry out the work of fixing a base to another existing steel support installed on the tunnel entrance side of the existing steel support, and to rotate the width adjustment rod by pressing it against the base with a jack.

[0011] The support unit of the present invention comprises a steel support consisting of a pair of flanges and a web suspended horizontally between the pair of flanges, a weight-bearing tie fixed to the side of the web at the tunnel mouth, and a support member suspended horizontally between the pair of flanges at a position corresponding to the weight-bearing tie on the face side of the steel support. The weight-bearing tie comprises a horizontal member (horizontal member) whose base end is fixed to the steel support so that its horizontal or tip end is higher than its base end, a locking member formed at the tip of the horizontal member, and a diagonal member whose tip end is fixed to the tip end of the horizontal member and whose base end is fixed to the steel support above the horizontal member. The locking member can be locked to the support member.

[0012] By using such a shoring unit, it becomes possible to easily connect new steel supports to existing steel supports using weight-bearing ties and horizontal ties. In addition, the weight of the new steel supports is transferred to the existing steel supports by the weight-bearing ties, ensuring the stability of the new steel supports before they are reinforced.

[0013] The receiving member may be a steel rod suspended across the pair of flanges. In this case, it is preferable that the locking member is made of a plate material having a recess into which the receiving member can be inserted, and that the tip of the locking member has a shape that abuts against the web when the receiving member is inserted into the recess.

[0014] The receiving member may be a steel material having an inverted L-shaped cross section, consisting of a first piece arranged vertically and a second piece having a surface parallel to the cross member, and is hung horizontally on the pair of flanges with a gap between the hole mouth end of the second piece and the web. In this case, the locking member is made of a plate material with the tip of the cross member welded to the face side surface, and it is preferable that the face side surface abuts against the web directly or via a spacer fixed to the face side surface with the locking part protruding below the cross member inserted into the gap.

[0015] The support leg position correction device of the present invention corrects the position of the leg of a new steel support connected to a first existing steel support, which is an existing steel support arranged at a position closest to the face. The support leg position correction device includes a base fixed to a second existing steel support, which is one of the existing steel supports arranged on the tunnel mouth side of the first existing steel support, a width adjustment bar whose base end is placed on the base and whose tip end is inserted into a space surrounded by the flange and web of the leg of the new steel support, and a jack bolt attached to the base. The width adjustment bar is used by abutting against the first existing steel support. In addition, the jack bolt can apply a pressing force to the width adjustment bar to push it toward the second existing steel support.

[0016] With this support leg position correction device, the position of the legs of a newly constructed arch-shaped steel support, whose legs have spread out due to its own weight, can be corrected by using a width adjustment rod, without the worker entering the risk of skin falling area near the face.

[0017] In addition, it is desirable to use a base that has a magnetic section that generates a magnetic force that can be fixed to the second existing steel support, and an arm section that is rotatable around a vertical axis relative to the magnetic section. Effect of the Invention

[0018] According to the shoring construction method, shoring unit, and shoring leg position correction device of the present invention, it is possible to improve workability during shoring construction by preventing workers from entering areas near the face that are at risk of skin falling. [Brief description of the drawings]

[0019] [Figure 1] FIG. 2 is a cross-sectional view showing an overview of the tunnel. [Diagram 2] FIG. 2 is a diagram showing the installation status of the support unit of the first embodiment, where (a) is a cross-sectional view and (b) is a plan view. [Diagram 3] 1(a) and (b) are cross-sectional views of a steel support according to a first embodiment. [Figure 4] 1A to 1C are diagrams showing the weight-bearing connecting material of the first embodiment, where (a) is a side view, (b) is a plan view, and (c) is a front view as seen from the mine entrance side. [Diagram 5] 1A and 1B are diagrams showing the joint between the weight-bearing connecting material of the first embodiment and an existing steel support, in which (a) is after joining and (b) is before joining. [Figure 6] FIG. 13 is a side view showing a horizontal tie. [Figure 7] FIG. 1 shows a diagram of a horizontal tie, 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] FIG. 11 is a cross-sectional view showing a working state of a connecting process. [Figure 9] FIG. 9 is a cross-sectional view showing a working state of a connecting step following FIG. 8. [Figure 10] 11A and 11B are diagrams showing a working state of a leg position correcting process, in which (a) is a cross-sectional view and (b) is a plan view. [Figure 11] 4A is a plan view showing the base of the support leg position correction device, FIG. 4B is a plan view of the width adjustment rod of the support leg position correction device, and FIG. 4C is a side view of the width adjustment rod. [Figure 12] FIG. 11 is a cross-sectional view showing the working status of the leg position correcting step following FIG. 10. [Figure 13] A cross-sectional view showing a support unit of the second embodiment. [Figure 14] 11A and 11B are cross-sectional views showing the joint between the weight-bearing connecting member of the second embodiment and the newly constructed steel support, where (a) is the base end of the horizontal member and (b) is the base end of the diagonal member. [Figure 15] 1A is a cross-sectional view showing the locking member and the receiving member of the existing steel support, and FIG. 1B is a front view of the locking member. [Figure 16] 5A to 5C are cross-sectional views showing the locking member and the receiving member in a connecting process, in which (a) is in a close proximity state, (b) is in a contact state, and (c) is in a connected state. [Figure 17] A cross-sectional view showing a support unit of a third embodiment. [Figure 18] 11A and 11B are cross-sectional views showing the joint between the weight-bearing connecting material of the third embodiment and the newly constructed steel support, where (a) is the base end of the horizontal member and (b) is the base end of the diagonal member. [Figure 19] A cross-sectional view showing the locking member and the receiving member of the existing steel support. [Figure 20] 5A to 5C are cross-sectional views showing the locking member and the receiving member in a connecting process, in which (a) is in a close proximity state, (b) is in a contact state, and (c) is in a connected state. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] First Embodiment In the first embodiment, a case where a tunnel is constructed by NATM will be described. As shown in Fig. 1, a tunnel T is stabilized by blocking the exposed natural ground surface Gs by excavating the natural ground G with a support 1 made of sprayed concrete 2 or steel supports. In addition, auxiliary construction methods such as pre-supporting, head bolting, and leg reinforcement may be used in combination during tunnel construction as necessary.

[0021] In this embodiment, construction of the upper half T1 above the spring line SL (upper half excavation and formation of the support 1) is carried out first, and then construction of the lower half T2 (lower half excavation or side bench excavation and formation of the support 1) is carried out at a predetermined interval. Note that construction of the lower half T2 is carried out at a position away from the construction site of the upper half T1 so as to ensure time until the ground of the upper half T1 is stabilized.

[0022] The construction of the upper half T1 involves first excavating the natural ground G to form a borehole (tunnel T) (excavation process). 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 is set to 1.0 to 1.2 m in this embodiment.

[0023] 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 shotcrete 2 and steel supports 3, 30. The construction of the support 1 includes a shoring assembly operation and a spraying operation. The construction (spraying operation) of the shotcrete 2 may be performed in two steps, a primary spraying and a secondary spraying, or the shotcrete 2 of a predetermined thickness may be formed in one step.

[0024] The shoring assembly method (shoring assembly work) will be described below. The shoring assembly method of this embodiment includes an erection step, a connection step, and a leg position correction step.

[0025] In the erection process, as shown in Figure 2(a), heavy machinery such as an erector M is used to excavate the ground G to a specified length inside the tunnel, and a shoring unit 7 having a weight-bearing tie member 4, a horizontal tie member 5 and a support member 6 (see Figure 3) attached to a newly constructed steel shoring 3 is erected near the face inside the tunnel.

[0026] As shown in Fig. 3, the new steel support 3 is formed by processing a steel material (H-shaped steel) consisting of a pair of flanges 31, 31 and a web 32 horizontally connected to the pair of flanges 31, 31. The pair of left and right new steel supports 3 are connected at their tops to form an arch shape as shown in Fig. 1.

[0027] The weight-bearing tie member 4 is fixed to the side surface of the tunnel entrance of the web 32. As shown in Fig. 4(a), the weight-bearing tie member 4 includes a horizontal member 41 whose base end is fixed to the newly constructed steel support 3, a locking member 42 formed at the tip of the horizontal member 41, and a diagonal member 43 whose tip end is fixed to the tip end of the horizontal member 41 and whose base end is fixed to the newly constructed steel support 3 above the horizontal member 41.

[0028] The horizontal member 41 is made of a steel pipe. A nut 44 is fixed inside the base end of the horizontal member 41. The horizontal member 41 is fixed to the web 32 of the newly constructed steel support 3 by screwing a bolt that has passed through the web 32 into the nut 44. In addition, as shown in Fig. 4(b), a slit 45 into which a locking member 42 can be inserted is formed at the tip of the horizontal member 41.

[0029] The diagonal member 43 is made of a steel pipe. In this embodiment, the steel pipe constituting the diagonal member 43 and the steel pipe constituting the horizontal member 41 are made of the same material. A fixing plate 47 is fixed to the base end of the diagonal member 43. A through hole is formed in the fixing plate 47, and a nut 44 is fixed to the fixing plate 47 at a position corresponding to the through hole. The diagonal member 43 is fixed to the web 32 of the newly constructed steel support 3 by screwing a bolt that has passed through the web 32 into the nut 44 of the fixing plate 47. In addition, a slit 45 into which a locking member 42 can be inserted is formed at the tip of the diagonal member 43, as shown in FIG. 4(c).

[0030] 4(a) and (c), the locking member 42 is made of a plate material having a recess 46 formed therein into which the receiving member 6 (first receiving member 61) can be inserted. The locking member 42 is welded to the tip end of the horizontal member 41 and the tip end of the diagonal member 43 in a state where it is inserted into the slit 45 of the horizontal member 41 and the slit 45 of the diagonal member 43. That is, the locking member 42 in this embodiment is fixed integrally to the tip end of the horizontal member 41 and forms part of the tip end of the horizontal member 41. The diagonal member 43 is fixed to the tip end of the horizontal member 41 via the locking member 42.

[0031] As shown in FIG. 5(a), the locking member 42 is locked to the first receiving member 61 by inserting the first receiving member 61 into the recess 46. The planar distance from the recess 46 to the tip of the locking member 42 is equal to the distance from the first receiving member 61 to the web 32, and as shown in FIG. 5(b), the locking member 42 is lowered from above the first receiving member 61 with the tip of the locking member 42 abutting against the web 32 of the existing steel support, so that the first receiving member 61 is inserted into the recess 46. That is, the locking member 42 has a length such that the tip abuts against the web 32 of the existing steel support with the first receiving member 61 inserted into the recess 46. In addition, the tip of the locking member 42 is inclined so as to protrude toward the tunnel mouth as it goes upward (toward the diagonal member 43), and has a shape that does not come into contact with the bolt B for fixing the horizontal member 41 provided on the existing steel support.

[0032] The horizontal tie 5 is fixed to the tunnel mouth side of the web 32 of the new steel support 3. In this embodiment, the horizontal tie 5 is fixed with its base end (the end on the face K side) in contact with the web 32 of the new steel support 3, as shown in Fig. 6. The horizontal tie 5 is made of a steel pipe, and a nut 51 is welded to the inner hollow portion of the base end of the horizontal tie 5, as shown in Fig. 7(a). The horizontal tie 5 is fixed to the new steel support 3 by fastening a bolt B, which is inserted through the web 32 of the new steel support 3, to the nut 51, as shown in Fig. 6.

[0033] 7(b) to (d), a connecting member 52 is provided at the tip (the end on the wellhead side) of the horizontal tie 5. The connecting member 52 has a rectangular base 53 in plan view and a triangular locking portion 54 in plan view, and is formed by bending a steel plate shaped like an arrow in plan view into an inverted V shape.

[0034] The connecting member 52 is fixed to the horizontal tie 5 by welding the inner surface of the base 53 to the tip of the horizontal tie 5. A part of the base 53 protrudes from the tip face of the horizontal tie 5 toward the mine mouth, and a gap (accommodation section) capable of accommodating the receiving member 6 is formed between the tip face of the horizontal tie 5 and the locking section 54. The protruding length of the connecting member 52 from the tip of the horizontal tie 5 is set to a length that abuts on the web 32 of the existing steel support 30 to which the tip of the locking section 54 is joined.

[0035] The locking portion 54 has a width greater than that of the base 53, and has an inclined triangular (trapezoidal) shape with the sides narrowing toward the wellhead. That is, the end of the locking portion 54 on the base 53 side (horizontal tie 5 side) protrudes laterally beyond the base 53. The length of the locking portion 54 protruding laterally from the base 53 is approximately the same as the diameter (width) of the horizontal tie 5.

[0036] As shown in FIG. 3(a), the receiving member 6 is made of a steel bar and is horizontally supported on a pair of flanges 31, 31 on the face side of the web 32. In this embodiment, the receiving member 6 provided at a position corresponding to the weight-bearing tie member 4 is called the first receiving member 61, and the receiving member 6 provided at a position corresponding to the horizontal tie member 5 is called the second receiving member 62. Both ends of the receiving member 6 are welded to the flanges 31, 31. When the dimension between the flanges 31 is large, the end fixation degree is increased by bending both ends of the material (steel bar) constituting the receiving member 6 and welding them to the flanges 31, so that a steel bar of a common diameter can be used. Also, as shown in FIG. 3(a) and (b), regardless of the size of the newly constructed steel support 3, a common locking member 42 or connecting member 52 can be used by making the dimension from the web 32 to the receiving member 6 constant.

[0037] In the connection process, the shoring unit 7 (new steel shoring 3) is connected to the existing steel shoring 30 installed on the tunnel mouth side. To connect the shoring unit 7 to the existing steel shoring 30, first, the locking member 42 is locked to the first receiving member 61, as shown in FIG. 5(a). The locking member 42 is lowered from above with its tip abutting the web 32 of the existing steel shoring 30, as shown in FIG. 5(b), to insert the first receiving member 61 into the recess 46, as shown in FIG. 5(a). At this time, the new steel shoring 3 is inclined so that its head is closer to the face side than the foot, as shown in FIG. 8.

[0038] Next, as shown in Fig. 9, the erector M is used to pull the head of the new steel support 3 toward the existing steel support 30, thereby erecting the new steel support 3 vertically, and the connecting member 52 of the horizontal tie 5 is attached to the second support member 62. The new steel support 3 is made vertical by rotating the first support member 61 to which the locking member 42 is locked, around its axis. When the connecting member 52 of the horizontal tie 5 is attached to the second support member 62, the new steel support 3 becomes parallel to the existing steel support 30 and is erected vertically. At this time, the legs of the new steel support 3 are not on the ground and are in a floating state.

[0039] In the leg position correction process, as shown in Figs. 10(a) and (b), a support leg position correction device 8 is used to correct the position of the leg of the newly constructed steel support 3. The support leg position correction device 8 corrects the position of the leg of the new steel support 3 connected to the first existing steel support 301, which is the existing steel support 30 arranged at the position closest to the face. As shown in Fig. 10(b), the support leg position correction device 8 includes a base 81, a width adjustment bar 82, and a jack bolt 83.

[0040] The pedestal 81 is fixed to a second existing steel support 302, which is one of the existing steel supports 30 provided on the tunnel entrance side of the first existing steel support 301. As shown in Fig. 11(a), the pedestal 81 includes a magnetic section 84 that generates a magnetic force capable of fixing the pedestal 81 to the second existing steel support 302, and an arm section 85 that extends laterally from the magnetic section 84. The arm section 85 is connected to the magnetic section 84 via a hinge bolt 86, and is rotatable with respect to the magnetic section 84 around a vertical axis (the central axis of the hinge bolt 86).

[0041] The width shifting bar 82 is made of a long steel material. In this embodiment, a square steel pipe (so-called square pipe) having a rectangular cross section is used. With the base end of the width shifting bar 82 placed on the base 81, the tip end is inserted into the space surrounded by the flanges 31, 31 and the web 32 of the leg of the newly constructed steel support 3. As shown in Figs. 11(b) and (c) , a reinforcing plate 87 is fixed to the tip of the width shifting bar 82. The reinforcing plate 87 is welded in a state where it is inserted into a slit formed in the tip of the square steel pipe. In addition, a protective plate 88 is fixed to a predetermined position from the tip of the square steel pipe (in this embodiment, within a range of 900 to 1200 mm from the tip of the square steel pipe).

[0042] 11(a), the jack bolt 83 is provided at the tip of the pedestal 81. The jack bolt 83 is attached to a reaction plate 89 fixed to the tip of the pedestal 81 so as to be able to advance and retreat. The jack bolt 83 can apply a pressing force to the width adjustment bar 82 placed on the pedestal 81 to press it toward the second existing steel support 302 by pressing the reaction plate 89 toward the magnetic section 84.

[0043] When correcting the position of the legs of the newly constructed steel support 3, the first step is to fix the base 81 to another existing steel support 30 (second existing steel support 302) installed on the tunnel entrance side of the existing steel support 30 (first existing steel support 301). The base 81 is fixed by magnetic force by activating the magnetic section 84 while the magnetic section 84 is in contact with the flange 31 of the existing steel support 30 .

[0044] Next, the tip of the width adjustment rod 82 is inserted into the space surrounded by the flanges 31, 31 of the leg of the new steel support 3 and the web 32, and the base end of the width adjustment rod 82 is placed on the base 81. At this time, the width adjustment rod 82 (protective plate 88) is abutted against the flange 31 of the first existing steel support 301.

[0045] Next, the position of the leg of the new steel support 3 is corrected by rotating the width adjustment rod 82 using the contact point between the width adjustment rod 82 and the first existing steel support 301 as a fulcrum. The width adjustment rod 82 is rotated by pressing it against the second existing steel support 302 with a jack bolt 83 on the base 81.

[0046] After correcting the position of the legs of the new steel support 3, the legs are hardened with shotcrete 2 and the shotcrete 2 is sprayed onto the ground as shown in Fig. 12. Then, the support leg position correction device 8 is removed.

[0047] If the erector is equipped with a spraying device, the erector is used to correct the position of the legs of the new steel support 3, and the legs are solidified with sprayed concrete 2, which is then sprayed onto the ground. After that, the erector is released.

[0048] According to the shoring assembly method of this embodiment, it is possible to easily connect the new steel shoring 3 to the existing steel shoring 30 by the weight-bearing ties 4 and horizontal ties 5. In addition, since there is no need to tighten the bolts manually, the steel shoring can be connected using an erector device having a pair of hands that can grasp the steel shoring, and manual work on the exposed ground before the shoring is completed or directly below the primary shotcrete can be omitted.

[0049] The weight-bearing connecting material 4 transmits the weight of the newly constructed steel support 3 to the existing steel support 30, thereby ensuring the stability of the newly constructed steel support 3 before the footing is consolidated. Furthermore, the width adjustment rod 82 makes it possible to correct the position of the legs of the newly constructed arch-shaped steel support 3, whose legs have spread out due to their own weight, without the worker having to enter the area near the face where there is a risk of skin falling.

[0050] The width adjustment bar 82 is rotated by a jack (jack bolt), reducing the burden on the worker. Furthermore, the width adjustment bar 82 can be rotated relatively easily by using the principle of leverage. Since the base 81 is fixed via the magnetic portion 84, it is easy to attach and detach.

[0051] Second Embodiment In the second embodiment, a case where a tunnel is constructed by NATM, as in the first embodiment, will be described. The tunnel T is stabilized by blocking the ground surface Gs exposed by excavating the ground G with a support 1 made of shotcrete 2, steel shoring, etc. The support 1 in this embodiment includes the shotcrete 2 and steel shoring 3, 30. The construction of the shoring 1 includes a shoring assembly work and a spraying work (see FIG. 1). The shoring assembly method (shoring assembly work) of the second embodiment will be described below. The shoring assembly method of this embodiment includes an erection process, a connection process, and a leg position correction process.

[0052] In the erection process, heavy machinery such as an Erector M is used to excavate the ground G to a specified length inside the tunnel, and a support unit 7 having a weight-bearing tie member 4, a horizontal tie member 5 and a support member 6 attached to a newly constructed steel support 3 is erected near the face inside the tunnel (see Figure 2(a)).

[0053] The new steel support 3 is formed by processing a steel material (H-shaped steel) consisting of a pair of flanges 31, 31 and a web 32 that is horizontally supported by the pair of flanges 31, 31. The pair of left and right new steel supports 3 are connected at their tops to form an arch shape, as shown in FIG.

[0054] The weight-bearing tie member 4 is fixed to the side of the tunnel entrance of the web 32 of the new steel support 3 (existing steel support 30) as shown in Fig. 13. The weight-bearing tie member 4 includes a horizontal member 40 whose base end is fixed to the new steel support 3, a locking plate 48 (locking member) formed at the tip of the horizontal member 40, and a diagonal member 43 whose tip end is fixed to the tip end of the horizontal member 40 and whose base end is fixed to the new steel support 3 above the horizontal member 40.

[0055] The horizontal member 40 is made of a steel pipe and is inclined so that the tip end is higher than the base end. As shown in Fig. 14(a), a fixing plate 47 is fixed to the base end of the horizontal member 40. The fixing plate 47 has a bolt hole 471 with a threaded inner surface. The horizontal member 40 is fixed to the web 32 by screwing a bolt B, which has passed through the web 32 of the new steel support 3, into the bolt hole 471 of the fixing plate 47.

[0056] The diagonal member 43 is made of a steel pipe. In this embodiment, the steel pipe constituting the diagonal member 43 and the steel pipe constituting the horizontal member 40 are made of the same material. As shown in FIG. 14(b), a fixing plate 47 is fixed to the base end of the diagonal member 43. The fixing plate 47 has a bolt hole 471 with a threaded inner surface. The diagonal member 43 is fixed to the web 32 by screwing a bolt B, which has been passed through the web 32 of the newly constructed steel support 3, into the bolt hole 471 of the fixing plate 47.

[0057] As shown in Figs. 15(a) and (b), the locking plate 48 is made of a rectangular steel plate fixed to the tip (the mouth side end) of the horizontal member 40. The tip of the horizontal member 40 is welded to the lower part of the face side of the locking plate 48. That is, in this embodiment, the locking plate 48 is included in the tip part of the horizontal member 40. Also, the tip of the diagonal member 43 is welded to the upper part of the face side of the locking plate 48. That is, the diagonal member 43 is fixed to the tip part of the horizontal member 40 via the locking plate 48 (locking member). At the lower end of the locking plate 48, a locking part 481 is formed that protrudes downward from the lower end of the horizontal member 40. In this embodiment, the locking part 481 is a protrusion formed at the center of the lower end of the locking plate 48 by cutting out the lower end corner of the locking plate 48. The protruding length (height) of the locking part 481 is at least equal to or greater than the plate thickness of the receiving member 6.

[0058] The details of the horizontal tie material 5 are similar to those of the horizontal tie material 5 in the first embodiment, and therefore a detailed description thereof will be omitted. In the new steel support 3 of this embodiment, receiving members 6 (third receiving member 63 and second receiving member 62) are provided at positions corresponding to the weight-bearing tie members 4 and the horizontal tie members 5. Details of the second receiving member 62 are similar to those of the second receiving member 62 of the first embodiment, and therefore detailed description thereof will be omitted.

[0059] As shown in FIG. 14(a), the third support member 63 is horizontally supported on the face side end of a pair of flanges 31, 31 of the new steel support 3 at a position corresponding to the weight-bearing joint member 4. The third support member 63 is made of a steel material having a V-shaped (inverted L-shaped) cross section, which has a first piece 631 arranged vertically and a second piece 632 extending from the upper end of the first piece 631 to the web 32 side. The first piece 631 is parallel to the end face of the flange 31, and the second piece 632 is parallel to the horizontal member 40. The third support member 63 is provided with a gap S between the mouth side end of the second piece 632 and the web 32, into which the lower end (locking portion 481) of the locking plate 48 can be inserted. The third support member 63 is provided so that the height position of the upper surface of the second piece 632 and the lower surface of the horizontal member 40 coincides. That is, the third receiving member 63 is welded to the pair of flanges 31, 31 with the second piece 632 positioned higher than the bolt B screwed into the fixing plate 47 of the cross member 40. Both ends of the first piece 631 are welded to the face side end of each flange 31, and both ends of the second piece 632 are welded to the inner surface of each flange 31.

[0060] As shown in FIG. 15(a), the locking plate 48 is locked to the third receiving member 63 by inserting the locking portion 481 into the gap S between the third receiving member 63 and the web 32 of the existing steel support 30. When the locking portion 481 is locked to the third receiving member 63 (inserted into the gap S), the hole-mouth side surface of the locking plate 48 abuts against the web 32 of the existing steel support 30. In other words, the length of the weight-bearing connecting member 4 in the tunnel axis direction (the horizontal distance from the base end of the horizontal member 40 or the base end of the diagonal member 43 to the hole-mouth side end face of the locking plate 48) is the same as the distance from the hole-mouth side surface of the web 32 of the new steel support 3 to the face side surface of the web 32 of the existing steel support 30.

[0061] In the connecting step, the shoring unit 7 (new steel shoring 3) is connected to the existing steel shoring 30 installed on the tunnel mouth side (see FIG. 13). The shoring unit 7 is connected to the existing steel shoring 30 by bringing the locking plate 48 close to the third support member 63 as shown in FIG. 16(a), and then placing the locking plate 48 on the second piece 632 of the third support member 63 as shown in FIG. 16(b). Since the first piece 631 is provided on the front surface of the third support member 63, the tip end portion (locking plate 48) of the horizontal member 40 is prevented from entering under the second piece 632 even if the tip end portion (locking plate 48) of the horizontal member 40 is positioned lower than the second piece 632 as shown in FIG. 16(b).

[0062] Next, by pulling the new steel support 3 toward the existing steel support 30, as shown in FIG. 16(c), the locking portion 481 of the locking plate 48 is inserted into the gap S between the third support member 63 and the web 32, and the locking plate 48 is locked to the third support member 63. Accordingly, the connecting member 52 of the horizontal tie 5 is attached to the second support member 62. At this time, the new steel support 3 is erected vertically in parallel with the existing steel support 30 (see FIG. 13). In addition, the legs of the new steel support 3 are not in contact with the ground and are in a floating state.

[0063] In the leg position correction process, a shoring leg position correction device 8 is used to correct the position of the leg of the newly constructed steel shoring 3 (see FIG. 10). Note that the details of the leg position correction process are similar to those described in the first embodiment, and therefore a detailed description thereof will be omitted.

[0064] According to the support assembly method of this embodiment, it is possible to obtain the same effects as the support assembly method of the first embodiment. When the legs of the new steel support 3 are floating, the new steel support 3 is supported by the existing steel support 30 via the weight-bearing ties 4. At this time, the vertical force acting via the weight-bearing ties 4 is transmitted to the existing steel support 30 via the receiving member 6 (third receiving member 63). In addition, the horizontal force acting via the diagonal member 43 is transmitted to the web of the existing steel support 30 via the locking plate 48.

[0065] In addition, according to the shoring assembly method of this embodiment, the first piece 631 of the third support member 63 prevents the tip of the weight-bearing tie member 4 (horizontal tie member 5) from entering under the support member 6. This makes it easier to position the new steel support 3 when joining the new steel support 3 to the existing steel support 30. If the weight-bearing tie member 4 enters under the support member 6, it is necessary to push the new steel support 3 toward the face while preventing the weight-bearing tie member 4 and the horizontal tie member 5 from contacting the support member 6, adjust the height, and then pull it back again, which is time-consuming. On the other hand, in this embodiment, the tip of the weight-bearing tie member 4 (horizontal tie member 5) is prevented from entering under the support member 6, so such position adjustment is not required. By reducing the width of the locking portion 481, the locking plate 48 can be easily inserted into the gap S.

[0066] <Third embodiment> In the third embodiment, a case where a tunnel is constructed by NATM, as in the first and second embodiments, will be described. A tunnel T is stabilized by blocking the ground surface Gs exposed by excavating the ground G with a support 1 made of sprayed concrete 2, steel shoring, etc. (see FIG. 1). The support 1 in this embodiment includes the shotcrete 2 and steel shoring 3, 30. The construction of the shoring 1 includes a shoring assembly work and a spraying work. A shoring assembly method (shoring assembly work) of the third embodiment will be described below. The shoring assembly method of this embodiment includes an erection process, a connection process, and a leg position correction process.

[0067] In the erection process, heavy machinery such as an Erector M is used to excavate the ground G to a specified length inside the tunnel, and a support unit 7 having a weight-bearing tie member 4, a horizontal tie member 5 and a support member 6 attached to a newly constructed steel support 3 is erected near the face inside the tunnel (see Figure 2(a)).

[0068] The weight-bearing tie member 4 is fixed to the side of the tunnel entrance of the web 32 of the steel support, as shown in Fig. 17. The weight-bearing tie member 4 includes a horizontal member 41 (cross member 40) whose base end is fixed to the steel support, a locking plate 48 (locking member) formed at the tip of the horizontal member 41, and a diagonal member 43 whose tip end is fixed to the tip end of the horizontal member 41 and whose base end is fixed to the new steel support 3 above the horizontal member 41.

[0069] The horizontal member 41 is made of a steel pipe and is installed almost horizontally. As shown in Fig. 18(a), a nut 44 is fixed inside the base end of the horizontal member 41. The horizontal member 41 is fixed to the web 32 of the newly constructed steel support 3 by screwing a bolt B, which has passed through the web 32, into the nut 44.

[0070] The diagonal member 43 is made of a steel pipe. In this embodiment, the steel pipe constituting the diagonal member 43 and the steel pipe constituting the horizontal member 41 are made of the same material. As shown in FIG. 18(b), a fixing plate 47 is fixed to the base end of the diagonal member 43. The fixing plate 47 has a bolt hole 471 with a threaded inner surface. The diagonal member 43 is fixed to the web 32 (steel support) by screwing a bolt B that has passed through the web 32 of the newly installed steel support 3 into the bolt hole 471 of the fixing plate 47.

[0071] 19, the locking plate 48 is made of a steel plate fixed to the tip of the horizontal member 41. A spacer 482 is fixed to the wellhead side of the locking plate 48. The spacer 482 is a member having a thickness equal to or greater than that of the head of the bolt B screwed into the nut 44 of the horizontal member 41. There are no limitations on the material constituting the spacer 482, and it may be, for example, a steel plate, a member formed by processing a steel plate, a nut, etc. Other details of the locking plate 48 are similar to those described in the second embodiment, so detailed description thereof will be omitted.

[0072] The details of the horizontal tie material 5 are similar to those of the horizontal tie material 5 in the first embodiment, and therefore a detailed description thereof will be omitted. In the new steel support 3 of this embodiment, a fourth support member 64 is provided at a position corresponding to the weight-bearing tie member 4, and a second support member 62 is provided at a position corresponding to the horizontal tie member 5. The details of the second support member 62 are similar to those of the second support member of the first embodiment, and therefore a detailed description thereof will be omitted.

[0073] As shown in FIG. 18(a), the fourth support member 64 is horizontally supported on the face side end of a pair of flanges 31, 31 of the new steel support 3 at a position corresponding to the weight-bearing connecting member 4. The fourth support member 64 is made of a steel material having an inverted L-shaped cross section, which has a first piece 641 arranged vertically and a second piece 642 extending from the upper end of the first piece 641 to the web 32 side. The first piece 641 is parallel to the end face of the flange 31, and the second piece 642 is horizontal (parallel to the horizontal member 41). The fourth support member 64 is welded to the pair of flanges 31, 31 so that the height positions of the upper surface of the second piece 632 and the lower surface of the horizontal member 41 are the same, with a gap S between the hole mouth side end of the second piece 642 and the web 32, allowing the lower end (locking portion 481) of the locking plate 48 to be inserted. That is, the fourth receiving member 64 is welded to the pair of flanges 31, 31 with the second piece 642 located at a position lower than the bolt B screwed into the nut 44 of the horizontal member 41. Both ends of the first piece 641 are welded to the face side end of each flange 31, and both ends of the second piece 642 are welded to the inner surface of each flange 31.

[0074] As shown in FIG. 19, the locking plate 48 is locked to the fourth support member 64 by inserting the locking portion 481 into the gap S between the fourth support member 64 and the web 32 of the existing steel support 30. Here, the length of the weight-bearing connecting member 4 in the tunnel axial direction (the total of the length of the horizontal member 41, the thickness of the locking plate 48, and the thickness of the spacer 482) is the same as the distance from the tunnel mouth side of the web 32 of the new steel support 3 to the face side of the web 32 of the existing steel support 30. Therefore, when the locking plate 48 is locked to the fourth support member 64, the spacer 482 abuts against the web 32 of the existing steel support 30. That is, the face side surface of the locking plate 48 abuts against the web 32 of the existing steel support 30 via the spacer 482 in a state where the locking portion 481 is locked to the fourth support member 64 (inserted into the gap S).

[0075] In the connection process, the shoring unit 7 (new steel shoring 3) is connected to the existing steel shoring 30 installed on the tunnel mouth side (see FIG. 17). The shoring unit 7 is connected to the existing steel shoring 30 by bringing the locking plate 48 close to the fourth support member 64 as shown in FIG. 20(a), and then placing the locking plate 48 on the second piece 642 of the fourth support member 64 as shown in FIG. 20(b). Since the first piece 641 is provided on the front surface of the fourth support member 64, even if the tip end portion (locking plate 48) of the horizontal member 41 is positioned lower than the second piece 642 as shown in FIG. 20(a), the tip end portion (locking plate 48) of the horizontal member 41 is prevented from penetrating below the second piece 642.

[0076] Next, by pulling the new steel support 3 toward the existing steel support 30, as shown in FIG. 20(c), the locking portion 481 of the locking plate 48 is inserted into the gap S between the fourth support member 64 (second piece 642) and the web 32, and the locking plate 48 is locked to the fourth support member 64. Accordingly, the connecting member 52 of the horizontal tie 5 is attached to the second support member 62. At this time, the new steel support 3 is erected vertically in parallel with the existing steel support 30 (see FIG. 17). In addition, the legs of the new steel support 3 are not in contact with the ground and are in a floating state.

[0077] In the leg position correction process, a shoring leg position correction device 8 is used to correct the position of the leg of the newly constructed steel shoring 3 (see FIG. 10). Note that the details of the leg position correction process are similar to those described in the first embodiment, and therefore a detailed description thereof will be omitted.

[0078] According to the support assembly method of this embodiment, it is possible to obtain the same effects as those of the support assembly method of the second embodiment. In addition, since a spacer is fixed to the locking member, even if a bolt for fixing the cross member is protruding from the face side of the web, force can be transmitted between the weight-bearing member (diagonal member) and the existing steel support via the spacer.

[0079] When the legs of the new steel support 3 are floating, the new steel support 3 is supported by the existing steel support 30 via the weight-bearing ties 4. At this time, the vertical force acting via the weight-bearing ties 4 is transmitted to the existing steel support 30 via the bearing member 6 (fourth bearing member 64). In addition, the horizontal force acting via the diagonal member 43 is transmitted to the web of the existing steel support 30 via the spacer 482.

[0080] The embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and the above-described components can be appropriately modified without departing from the spirit of the present invention. For example, the shape and dimensions of the corner members are not limited to those shown in the above embodiment, and may be determined appropriately.

[0081] In addition, the connection structure of the horizontal tie member 5 with the existing steel support 30 is not limited as long as it is possible to connect by pulling the new steel support 3. In addition, the configuration of the connecting member 52 of the horizontal tie member 5 is not limited to that shown in the above embodiment. The jack configuration is not limited to a jack bolt. The shape of the locking portion 481 is not limited and may be determined appropriately. [Explanation of symbols]

[0082] 1 Shoring 2. Shotcrete 3 New steel shoring 30 Existing steel support structure 31 Flange 32 Web 4. Self-weight support material 40 Lateral member 41 Horizontal Member 42 Locking member 43 Diagonal Member 46 Recess 48 Locking plate (locking member) 5 Horizontal Ties 52 Connecting member 6 Receiving member 61 First receiving member 62 Second receiving member 63 Third receiving member 7 Shoring Unit 8 Shoring leg position correction device 81 Pedestal 82 Width adjustment pole 83 Jack bolt (jack) K Face M Erector SL Spring Line T-Tunnel T1 upper half T2 lower half

Claims

1. an erection process in which a new steel support structure to which the weight-bearing tie members and horizontal tie members are attached is erected near the face; A connecting process of connecting the weight-bearing tie member and the horizontal tie member to an existing steel support provided on the tunnel mouth side of the new steel support; A support assembly method comprising: a leg position correction step of correcting the position of the leg of the newly installed steel support by a width adjustment bar; The weight-bearing connecting member includes a horizontal member having a base end fixed to the new steel support, a locking member formed at the tip of the horizontal member, and a diagonal member having a tip end fixed to the tip end of the horizontal member and a base end fixed to the new steel support above the horizontal member, A connecting member is formed at the tip of the horizontal connecting member, The existing steel support is formed with a first support member to which the locking member of the weight-bearing connecting material can be locked, and a second support member to which the connecting member can be attached is formed, The connecting step includes an operation of engaging the engaging member with the first receiving member; The newly constructed steel support is pulled toward the existing steel support, and the connecting member is attached to the second support member. In the leg position correction process, the tip of the width adjustment bar is inserted into a space surrounded by a flange and a web of the leg of the new steel support, and the width adjustment bar is abutted against the existing steel support; and correcting the position of the legs of the new steel support by rotating the width adjustment rod using the point of contact with the existing steel support as a fulcrum.

2. an erection process in which a new steel support structure to which the weight-bearing tie members and horizontal tie members are attached is erected near the face; A connecting process of connecting the weight-bearing tie member and the horizontal tie member to an existing steel support provided on the tunnel mouth side of the new steel support; A support assembly method comprising: a leg position correction step of correcting the position of the leg of the newly installed steel support by a width adjustment bar; The weight-bearing connecting member includes a horizontal member having a base end fixed to the newly constructed steel support so that the horizontal or tip end is higher than the base end, a locking member formed at the tip of the horizontal member, and a diagonal member having a tip end fixed to the tip end of the horizontal member and a base end fixed to the newly constructed steel support above the horizontal member, A connecting member is formed at the tip of the horizontal connecting member, The existing steel support is formed with a first support member to which the locking member of the weight-bearing connecting material can be locked, and a second support member to which the connecting member can be attached is formed, In the connecting step, the new steel support is pulled toward the existing steel support, the engaging member is engaged with the first support member, and the connecting member is attached to the second support member. In the leg position correction process, the tip of the width adjustment bar is inserted into a space surrounded by a flange and a web of the leg of the new steel support, and the width adjustment bar is abutted against the existing steel support; and correcting the position of the legs of the new steel support by rotating the width adjustment rod using the point of contact with the existing steel support as a fulcrum.

3. In the leg position correction process, a work of fixing a base to another existing steel support provided on the entrance side of the existing steel support is further performed, The support assembling method according to claim 1 or 2, characterized in that the width adjustment bar is rotated by pressing the width adjustment bar on the base with a jack.

4. A steel support structure including a pair of flanges and a web horizontally disposed on the pair of flanges; A weight-bearing tie fixed to the side of the wellhead of the web; A support unit including a support member that is horizontally supported on a pair of the flanges at a position corresponding to the weight support member on the face side of the steel support, The weight-bearing connecting member includes a horizontal member having a base end fixed to the steel support, a locking member formed at the tip of the horizontal member, and a diagonal member having a tip end fixed to the tip end of the horizontal member and a base end fixed to the steel support above the horizontal member, A support unit, characterized in that the locking member is capable of being locked to the receiving member.

5. A steel support structure including a pair of flanges and a web horizontally disposed on the pair of flanges; A weight-bearing tie fixed to the wellhead side of the web; A support unit including a support member that is horizontally supported on a pair of the flanges at a position corresponding to the weight support member on the face side of the steel support, The weight-bearing connecting member includes a horizontal member having a base end fixed to the steel support so that the horizontal or tip end is higher than the base end, a locking member formed at the tip of the horizontal member, and a diagonal member having a tip end fixed to the tip end of the horizontal member and a base end fixed to the steel support above the horizontal member, A support unit, characterized in that the locking member is capable of being locked to the receiving member.

6. The receiving member is a steel rod that is horizontally supported by the pair of flanges, The support unit described in claim 4 or claim 5, characterized in that the locking member is made of a plate material having a recess into which the receiving member can be inserted, and has a shape in which the tip abuts against the web when the receiving member is inserted into the recess.

7. The receiving member is a steel material having an inverted L-shape in cross section, which is made up of a first piece arranged vertically and a second piece having a surface parallel to the horizontal member, and is hung horizontally on the pair of flanges with a gap between the end of the second piece on the wellhead side and the web, The support unit described in claim 5, characterized in that the locking member is made of a plate material to which the tip of the cross member is welded to the face side surface, and the face side surface abuts against the web when the locking portion protruding downward of the cross member is inserted into the gap.

8. The support unit according to claim 7, characterized in that the locking member abuts against the web via a spacer fixed to the face side.

9. A support leg position correction device that corrects the position of a leg of a new steel support connected to a first existing steel support, which is an existing steel support arranged at a position closest to the face, A base fixed to a second existing steel support, which is one of the existing steel supports provided on the tunnel mouth side of the first existing steel support; A width adjustment rod having a base end placed on the base and a tip end inserted into a space surrounded by the flange and web of the leg of the newly installed steel support; and a jack bolt provided on the base, The width adjustment bar abuts against the first existing steel support, A support leg position correction device, characterized in that the jack bolt is capable of applying a pressing force to the width adjustment bar to push it toward the second existing steel support.

10. The base includes a magnetic portion that generates a magnetic force capable of being fixed to the second existing steel support, and an arm portion extending laterally from the magnetic portion, The support leg position correction device according to claim 9, wherein the arm portion is rotatable about a vertical axis relative to the magnetic portion.

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