PC steel wire insertion method in shield tunneling

Abstract

This invention provides a method for inserting PC steel wires that enables efficient and repeated smooth positioning of insertion devices, which have considerable weight, in the narrow working space of a shield tunnel, while positioning them at predetermined locations on the arc-shaped inner surface. [Solution] The system includes an installation step of lowering the PC steel wire insertion device 10 from a suspended state using an electric winch 57, positioning it, and installing it on the inner circumferential surface of the segment ring 52; an insertion step of inserting the PC steel wire 4 into the sheath pipe 3 by sandwiching the PC steel wire 4 between the drive roller 25 and driven roller 35 of the installed PC steel wire insertion device 10 and rotating the rotary motor 26; and a reinstallation step of lifting the PC steel wire insertion device 10, positioning it, lowering it, aligning the feeding direction X with the circumferential direction of the next row of sheath pipes 3, and reinstalling the PC steel wire insertion device 10 on the inner circumferential surface of the segment ring 52.

Description

Technical Field

[0001] The present invention relates to a method for inserting PC steel wires in the shield tunneling method. In particular, in a method such as an inner water pressure counteracting shield tunneling method for introducing prestress in the circumferential direction of a segment ring, the present invention relates to a method for inserting PC steel wires in a shield tunneling method using a PC steel wire insertion device for inserting PC steel wires into an embedded sheath pipe.

Background Art

[0002] As a shield tunneling method, for example, an inner water pressure counteracting shield tunneling method fills a shield tunnel communicating with a shaft used as a temporary water storage facility such as rainwater with pressure water that generates water pressure due to the head difference from the water level of the stored water in the shaft. Thus, a circumferential prestress (pre-compressive force) is introduced in advance into the segment ring so as to be able to withstand the circumferential tensile load applied by the water pressure. Also, in the inner water pressure counteracting shield tunneling method, PC steel wires are inserted into a sheath pipe continuously embedded in the circumferential direction of the segment ring, and prestress is applied to the inserted PC steel wires using a known pulling device such as a center hole jack. Preferably, both ends of the PC steel wires are fixed to a known fixing fitting such as an X anchor, thereby introducing a compressive force in the circumferential direction of the segment ring in advance so as to be able to withstand the circumferential tensile load due to the inner water pressure.

[0003] In such an inner water pressure counteracting shield tunneling method, the operation of inserting PC steel wires into the sheath pipe embedded in the segment ring has conventionally been performed manually by workers. However, when the weight of each PC steel wire becomes as large as about 10 kg, for example, a great deal of labor is required to insert the PC steel wires manually. Therefore, there has been a demand for the development of a device that enables such an operation of inserting PC steel wires to be performed smoothly and efficiently with less labor.

[0004] On the other hand, various devices have been developed for inserting PC steel wires into sheath pipes pre-embedded in concrete structures, for example, when constructing prestressed concrete structures (see, for example, Patent Documents 1 and 2). The PC steel wire automatic feeding device described in Patent Document 1 is used when inserting PC steel wires into sheath pipes pre-embedded in precast concrete members in a construction method that connects and integrates multiple precast concrete members, such as precast floor slabs, in a continuous manner. The PC steel wire automatic feeding device of Patent Document 1 has a rubber drive roller and a guide roller positioned parallel to the drive roller. Clamping grooves are formed on the circumferential surfaces of the drive roller and the guide roller, facing each other, and the PC steel wires are clamped in these clamping grooves. The PC steel wires are fed out by rotating the guide roller while pressing it against the drive roller. In the process of connecting multiple precast concrete members together using PC steel strands, the PC steel strand automatic feeding device is positioned and fixed on the upper surface of a flat precast concrete member, preferably in such a position that the PC steel strands are fed in a straight line relative to the sheath pipe.

[0005] Furthermore, the PC steel wire insertion machine described in Patent Document 2 is used to insert PC steel wires vertically downward from above the concrete structure to apply prestress, for example, in concrete structures such as above-ground PC tanks for LNG. The PC steel wire insertion machine of Patent Document 2 has a pair of upper and lower feed rollers with concave curved surfaces formed around their entire circumference, and moves the PC steel wire by passing it between the two feed rollers and feeding it in one direction by rotation. The PC steel wire insertion machine of Patent Document 2 is also installed on a flat dedicated stand and includes a guide section that guides the direction of the PC steel wire, which is fed out horizontally from the feed rollers, for example, to vertically downward, and a pressure adjustment section that applies pressure to at least one of the upper and lower feed rollers so that they are close together. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 9-67933 Public Relations [Patent Document 2] Japanese Patent Publication No. 2011-89368 Public Relations [Overview of the project] [Problems that the invention aims to solve]

[0007] However, while the PC steel wire automatic feeding device described in Patent Document 1 and the PC steel wire insertion machine described in Patent Document 2 enable efficient feeding of PC steel wires, including PC steel wire strands, towards sheath pipes embedded in precast concrete members or concrete structures with minimal effort, when installed on the top surface of a flat precast concrete member or on a flat dedicated stand, these conventional PC steel wire insertion devices are difficult to use as they are, for example, in the internal water pressure-resistant shield tunneling method when inserting PC steel wires circumferentially into the sheath pipes of assembled segment rings, because the working space inside the shield tunnel is narrow and the arc-shaped inner surface of the segment ring needs to be used as a working platform. For these reasons, there is a need to develop a new insertion device that has been improved to be suitable for construction inside a shield tunnel, enabling efficient and smooth insertion of PC steel wires into sheath pipes continuously embedded circumferentially in segment rings with minimal effort.

[0008] Furthermore, when inserting PC steel wires into sheath pipes continuously embedded in the circumferential direction of segment rings, and performing this work in the narrow working space inside a shield tunnel using the arc-shaped inner surface as a working platform, it is desirable that the reaction force when inserting the PC steel wires with the insertion device be obtained from the weight of the insertion device, which has considerable weight and is placed on the arc-shaped inner surface of the segment ring. In addition, the sheath pipes into which the PC steel wires are inserted are generally extended continuously in the circumferential direction and embedded in multiple rows in the axial direction for each ring. For this reason, there is a need for the development of a technology that can efficiently install such a considerably heavy insertion device at a predetermined position on the arc-shaped inner surface while positioning it in a narrow working space so that the PC steel wires can be repeatedly and smoothly fed out in the circumferential direction.

[0009] The present invention aims to provide a method for inserting PC steel wires in a shield tunneling method, which enables efficient and smooth insertion of PC steel wires into multiple rows of sheath pipes continuously embedded in a segment ring with minimal effort. This is achieved by positioning an insertion device, which has considerable weight, repeatedly and smoothly in a narrow workspace within the shield tunnel, allowing the PC steel wires to be fed out circumferentially, and efficiently installing it at a predetermined position on the arc-shaped inner surface. [Means for solving the problem]

[0010] The present invention relates to a shield tunneling method in which, after assembling a segment ring using concrete segments with pre-embedded sheath pipes, PC steel wires are inserted through notches provided in the assembled segment ring and tensioned and anchored to introduce prestress in the circumferential direction of the segment ring, the PC steel wire insertion method uses a PC steel wire insertion device for inserting the PC steel wires into the embedded sheath pipes, wherein the sheath pipes are continuously embedded in the circumferential direction of the segment ring and arranged in multiple rows at predetermined intervals in the axial direction, the PC steel wire insertion device comprises a lower divided weight body and an upper divided weight body, and when placed on the segment ring, has a considerable weight that can obtain the reaction force when inserting the PC steel wires by its own weight, and the lower divided weight body has a curved mounting bottom portion that is curved with a radius of curvature similar to that of the inner circumferential surface of the segment ring, and the PC steel wire insertion device is suspended by a lifting device installed in the central part of the hollow cross-section of the shield tunneling machine. Installation step: Position and lower the suspended PC steel wire insertion device from the state so that the feeding direction matches the circumferential direction of the row of sheath tubes in which the notches are arranged, and install the PC steel wire insertion device on the inner surface of the segment ring; Insertion step: Sandwich the PC steel wire between the drive roller and driven roller of the installed PC steel wire insertion device and rotate the motor to feed the PC steel wire toward the sheath tube with its end opening facing the notch, and insert it into the sheath tube; Insert the PC steel wire into the sheath tube The above objective is achieved by providing a method for inserting PC steel wires in a shield tunneling method, which includes a step of repositioning the PC steel wire insertion device, which is configured to include lifting the PC steel wire insertion device with the lifting device after inserting the PC steel wires, lowering the lifted PC steel wire insertion device with the lifting device, lowering the suspended PC steel wire insertion device while positioning it, and reinstalling the PC steel wire insertion device on the inner surface of the segment ring so that the feeding direction matches the circumferential direction of the sheath pipe in the next row in which the notches are arranged.

[0011] Furthermore, in the PC steel wire insertion method for the shield tunnel construction method of the present invention, it is preferable that the notches provided in each row of the sheath pipes, which are arranged in multiple rows at predetermined intervals in the axial direction, are arranged alternately at a first position and a second position in the circumferential direction, with their positions in the circumferential direction offset.

[0012] Furthermore, in the PC steel wire insertion method for the shield tunnel construction method of the present invention, it is preferable that the first position in the circumferential direction is the lowest position of the circular cross-section of the segment ring, and the second position is a position between one side end of the circular cross-section of the segment ring and the first position.

[0013] Furthermore, it is preferable that the PC steel wire insertion method in the shield tunnel construction method of the present invention is performed after rotating the erector device, which is assembled with segment rings, in the circumferential direction to retract the segment gripping portion upwards. [Effects of the Invention]

[0014] According to the PC steel wire insertion method in the shield tunnel construction method of the present invention, an insertion device having considerable weight can be repeatedly and smoothly positioned in a narrow working space inside the shield tunnel so as to feed the PC steel wire in the circumferential direction, and efficiently installed at a predetermined position on the arc-shaped inner surface. This allows the PC steel wire to be inserted into multiple rows of sheath pipes continuously embedded in the segment ring in the circumferential direction with little effort, efficiently and smoothly. [Brief explanation of the drawing]

[0015] [Figure 1] This is a schematic cross-sectional view illustrating a shield tunnel in which a PC steel wire insertion method in a preferred embodiment of the present invention is implemented. [Figure 2] This is a simplified cross-sectional view illustrating the process of inserting PC steel wires using a PC steel wire insertion device. [Figure 3]This diagram illustrates a PC steel wire insertion device. (a) is a front view, and (b) is a cross-sectional view along AA in (a). [Figure 4] The steel wire insertion device is explained below. (a) is a side view of Figure 3(a) viewed from the left, and (d) is a cross-sectional view of the hydraulic motor and motor fixing plate portion along BB in (a). [Figure 5] This is a schematic cross-sectional view illustrating a method for inserting PC steel wires in a shield tunneling method according to a preferred embodiment of the present invention. [Figure 6] Figure 5 is an inner circumferential view of a segment ring along CC, illustrating a method for inserting PC steel wires in a shield tunneling method according to a preferred embodiment of the present invention. [Figure 7] This is a schematic cross-sectional view of the main parts along DD in Figure 5, illustrating a method for inserting PC steel wires in a shield tunneling method according to a preferred embodiment of the present invention. [Modes for carrying out the invention]

[0016] A preferred embodiment of the present invention provides a method for inserting PC steel wires in a shield tunnel construction method, preferably as shown in Figures 1 and 2. In a shield tunnel 50 with an inner diameter of approximately 4 m, which serves as a temporary rainwater storage facility during heavy rains, preferably formed by a slurry shield method using a PC steel wire insertion device 10 for internal water pressure resistant shield tunnel construction, the method involves assembling segment rings 52 made of concrete segments 51 with pre-embedded sheath pipes 3 (see Figure 2) one ring at a time, and then inserting PC steel wires, preferably PC steel strands 4 (see Figure 2), into the sheath pipes 3 continuously embedded in the circumferential direction of each assembled segment ring 52, in the direction of the feed-out direction X. The PC steel wire insertion device 10 for shield tunneling is a device that enables the efficient and continuous insertion of PC steel wire strands 4 into the sheath pipe 3 embedded in the circumferential direction of the assembled segment ring 52 with minimal effort, in a shield tunneling method that pre-introduces circumferential prestress into the segment ring 52 in order to counteract the circumferential tensile load applied to the segment ring 52 by water pressure, for example, by filling the inside with pressurized water from rainwater that generates considerable water pressure.

[0017] And in this embodiment, the PC steel wire insertion device 10 is, as a shield tunnel method, after assembling the segment ring 52 with concrete segments 51 in which the sheath pipe 3 has been embedded in advance, from the notch 53 provided in the assembled segment ring 52, preferably the PC steel wire 4 is inserted as the PC steel wire, and prestress is introduced in the circumferential direction of the segment ring 52 by tensioning and fixing. For example, in the internal water pressure resistant shield tunnel method, it is an insertion device used when inserting the PC steel wire 4 into the embedded sheath pipe 3. As shown in FIGS. 3(a), (b) and FIGS. 4(a), (b) as well, it is composed of a lower divided weight body 20 having a single driving roller 25 and an upper divided weight body 30 having a pair of driven rollers 35, so that when placed on the segment ring 52, it is possible to obtain the reaction force when inserting the PC steel wire 4 by its own weight, and it has a considerable weight of about 72 kg for example. Further, the lower divided weight body 20 has a curved placement bottom surface portion 21 having a rectangular planar shape and curved with the same radius of curvature as the inner peripheral surface of the segment ring 52, and a driving roller 25 rotatable about a driving rotation axis 24 parallel to the width direction W of the curved placement bottom surface portion 21 is attached to the upper part. On the upper divided weight body 30, a pair of driven rollers 35 rotatable about a fixed rotation axis 34 parallel to the driving rotation axis 24 of the driving roller 25 are attached to the lower part in a state where they can be arranged on both sides sandwiching the driving roller 25 in the length direction L of the curved placement bottom surface portion 21. The lower divided weight body 20 and the upper divided weight body 30 are connected so as to be stacked vertically via the connecting pressing means 40, so that the PC steel wire 4 can be extended in the length direction L of the curved placement bottom surface portion 21 and sandwiched between the single driving roller 25 and the pair of driven rollers 35 with a pressing force applied. By rotationally driving the driving roller 25 in the state where the PC steel wire 4 is sandwiched, the sandwiched PC steel wire 4 is sent out toward the sheath pipe 3 with an end opening facing the notch 53.

[0018] In addition, in the present embodiment, the connecting pressing means 40 is preferably provided so as to project laterally from the side portions on both sides of the feeding direction X of the PC steel wire 4 in the lower divided weight body 20, and is provided between the lower fastening flange 41 having a screwing hole 41a and the upper fastening flange 42 having a through hole 42a, which is provided so as to project laterally from the side portions on both sides of the feeding direction X of the PC steel wire 4 in the upper divided weight body 30. It is composed of a long bolt member 43a and a nut member 43b that are each spanned and fastened.

[0019] In the present embodiment, as described above, the PC steel wire inserting device 10 includes a lower divided weight body 20 having a single driving roller 25, an upper divided weight body 30 having a pair of driven rollers 35, and a connecting pressing means 40 for connecting the lower divided weight body 20 and the upper divided weight body 30 so as to be stacked vertically.

[0020] The lower segmented weight body 20 has a rectangular planar shape having a predetermined width and length, a curved mounting bottom portion 21 that is curved in the longitudinal direction with a radius of curvature similar to that of the inner circumferential surface of the segment ring 52, a base portion 22 integrally joined to the upper side of the curved mounting bottom portion 21, a pair of upright support plate portions 23 that are erected from one side region of the width direction W of the curved mounting bottom portion 21 on the base portion 22 (see Figure 3(b)), a drive rotation shaft 24 that is rotatably supported on the upper part of these upright support plate portions 23 via bearings or the like and is arranged to extend parallel to the width direction W of the curved mounting bottom portion 21, and a drive roller 25 that is integrally joined to the drive rotation shaft 24 in the region between the pair of upright support plate portions 23 so as to pass through the drive rotation shaft 24 and is rotatable together with the drive rotation shaft 24. Furthermore, the drive roller 25 is rotated together with the drive rotation shaft 24 by the drive of the hydraulic motor 26, as the drive rotation shaft 24 is connected to the hydraulic motor 26 via a known chain coupling 29 in the region opposite to the drive roller 25, with the central upright support plate portion 23 in between. The hydraulic motor 26 is attached to the base portion 22 in the region opposite to the pair of upright support plate portions 23 in the width direction W of the curved mounting bottom surface portion 21, and is fixed to the motor fixing plate portion 27 which is erected parallel to the upright support plate portion 23, so that it protrudes on the opposite side from the upright support plate portion 23. The hydraulic motor 26 can rotate the drive rotation shaft 24 and the drive roller 25 by engaging the motor rotation shaft 26a, which rotatably penetrates and protrudes from the motor fixing plate portion 27, with the chain coupling 29.

[0021] The curved mounting base portion 21, which constitutes the lower segmented weight body 20, is located at the very bottom of the lower segmented weight body 20 and is the portion that allows the lower segmented weight body 20 to be placed on the inner surface of the segment ring 52 in a state of close contact with the arc-shaped curved inner surface of the segment ring 52. The curved mounting base portion 21 is curved in the length direction L, which is the longer side direction, with a radius of curvature similar to that of the inner surface of the segment ring 52, which has an inner diameter of, for example, about 4 m, and has a rectangular planar shape with a short side of about 300 mm and a long side of about 500 mm. The curved mounting base portion 21 is curved in the longitudinal direction L, which is also the feeding direction X of the PC steel strand 4, with a radius of curvature similar to that of the inner circumferential surface of the segment ring 52. This makes it possible to easily and smoothly install the PC steel wire insertion device 10 at a predetermined position on the inner circumferential surface of the segment ring 52, preferably by manual operation while the PC steel wire insertion device 10 is suspended, so that the feeding direction X of the PC steel strand 4 coincides with the circumferential direction of the segment ring 52, which is the direction in which the sheath pipe 3 embedded in the segment ring 52 extends. Preferably, for example, urethane rubber 21b is attached to the bottom surface 21a of the curved mounting base portion 21, which is the mounting surface on the segment ring 52. This makes it possible to more effectively prevent the PC steel wire insertion device 10 from shifting when a reaction force is applied to the PC steel wire insertion device 10 installed at a predetermined position on the inner circumferential surface of the segment ring 52 during the insertion of the PC steel strand 4. The thickness of the urethane rubber 21b can be, for example, 10 mm, but is not limited to this. On the upper side of the curved mounting base portion 21, opposite to the bottom surface 21a to which the urethane rubber 21b is attached, a base portion 22 is provided, which is integrally joined to it.

[0022] The base portion 22 is composed of, for example, three support plates 22a that extend in the longitudinal direction L and are arranged parallel to each other on the upper surface of the curved mounting bottom portion 21, and a base top plate 22b that is joined to these support plates 22a so as to connect their flat upper surfaces and cover the upper surfaces of the support plates 22a. The pair of upright support plates 23 that are erected from the base top plate 22b and rotatably support the drive rotation shaft 24 are integrally joined and provided, and the motor fixing plate 27 that supports and fixes the hydraulic motor 26 is integrally fixed and provided.

[0023] The pair of upright support plate sections 23 are made of horizontally elongated rectangular metal plate members and are preferably positioned in one side region in the width direction W of the base plate top plate 22b, directly above the support plate 22a of the base section 22, and are attached in an upright position from the base plate top plate 22b such that the long side is parallel to the length direction L of the curved mounting bottom surface section 21. Lower fastening flanges 41, which have screw holes 41a formed therein and constitute a connecting pressing means 40 described later, are provided on both sides of the upright support plate section 23 in the long side direction, extending laterally and straddling the pair of upright support plate sections 23. Furthermore, a cylindrical rod-shaped drive rotation shaft 24 is rotatably supported by these pair of upright support plate sections 23, with one end protruding towards the hydraulic motor 26, and is attached to the upper central part of the upright support section 23 so as to be parallel to the width direction W of the curved mounting bottom surface section 21. A drive roller 25, which is integrally joined to the drive rotating shaft 24, is positioned in the space between these pair of upright support plate sections 23.

[0024] The drive roller 25 is preferably made of a metal disc-shaped roller member with a V-shaped cross-sectional groove 25a formed on its outer circumference. The V-shaped cross-sectional shape of the groove 25a formed on the outer circumference of the drive roller 25 makes it easier to grip the PC steel strand 4, and allows for more efficient transmission of the force fed by the rotation of the drive roller 25. The angle between the two sides of the V-shape is preferably, for example, 90°.

[0025] As shown in Figures 4(a) and (b), the motor fixing plate portion 27, which is erected from the base plate top plate 22b, is made of a metal plate member having a vertically elongated, approximately pentagonal front shape with its upper edge cut in a V-shape, and the fixing base plate portion 27a is fixed to it at a right angle to its bottom edge. By fastening and fixing the fixing base plate portion 27a to the upper surface of the base plate top plate 22b by overlapping it, for example by bolting, the motor fixing plate portion 27 is positioned parallel to the pair of vertical support plate portions 23 in the area opposite to the pair of vertical support plate portions 23 in the width direction W of the base plate top plate 22b, and is provided in an erect state from the base plate top plate 22b. The known chain coupling 29 described above is provided in the portion between the motor fixing plate portion 27 and the vertical support plate portion 23 on the motor fixing plate portion 27 side for transmitting the rotational driving force from the hydraulic motor 26 to the drive rotation shaft 24. On the outer surface of the motor fixing plate portion 27, which is the side opposite to the chain coupling 29, the hydraulic motor 26 is fixed so as to protrude at a right angle, with the motor rotation shaft 26a protruding towards the chain coupling 29 (see Figure 3(b)).

[0026] The hydraulic motor 26 can be a known hydraulic motor, preferably having a rated pressure of 8.5 MPa, a rated output torque of 470 N°m, a rated flow rate of 57 L / min, a rated rotational speed of 138 rpm, a brake torque of 200 N°m, and a brake release pressure of 2.0 MPa. The hydraulic motor 26 is fixed to the side of the motor fixing plate portion 27 opposite to the chain coupling 29, for example, by bolt connection via a connecting flange 26b attached to the base end face, in a state that protrudes outward.

[0027] Furthermore, in this embodiment, on the upper part of the motor fixing plate portion 27, which is erected and attached from the base top plate 22b of the base portion 22, in the area above the portion to which the hydraulic motor 26 is attached, three suspension holes 28 are formed along the upper edge portion which is cut in a V-shape, in the upper central portion and on both sides one step lower than this.As will be described later, when the PC steel wire insertion device 10 is lifted up or lowered and positioned to face a predetermined direction on the inner circumferential surface of the segment ring 52, the tip locking portions of linear members 57a such as wires or chains extending from an electric winch 57, or linear members 58a extending from a lever block (registered trademark) 58, are locked into these suspension holes 28, as shown in Figures 1 and 5. These linear members 57a such as wires or chains extending from an electric winch 57, or linear members 58a extending from a lever block (registered trademark) 58, are attached to a support frame 56a such as an I-beam, which is supported by the shield tunneling machine 55 and installed inside it. This allows the PC steel wire insertion device 10 to be suspended from the support frame 56 via linear members 57a and 58a, and the suspended PC steel wire insertion device 10 can be moved up and down by, for example, an electric winch 57, and can also be moved to any position in the front, back, left, or right by, for example, pulling it in the left or right direction by a lever block (registered trademark) 58 or pushing it out in the front or back direction by a worker. Here, the hydraulic motor 26 protrudes from the motor fixing plate portion 27 on the opposite side from the pair of upright support plate portions 23, the drive rotation shaft 24 and the drive roller 25, which makes it possible to set the center of gravity of the PC steel wire insertion device 10 preferably to the portion of the motor fixing plate portion 27, making it possible to lift and lower the PC steel wire insertion device 10 in a more stable state, and to install it more smoothly in a predetermined position facing in the circumferential direction.

[0028] The upper divided weight body 30, which together with the lower divided weight body 20 constitutes the PC steel wire insertion device 10, is composed of an upper base body 33 having a U-shaped cross-section, which consists of a top plate 31 having a horizontally elongated rectangular flat planar shape, and a pair of horizontally elongated rectangular side-shaped extension support plate portions 32 attached to each other, extending downward from the edges along the long sides of both sides of the top plate 31; a pair of left and right fixed rotating shafts 34 that are positioned in the portion between the pair of extension support plate portions 32 of the upper base body 33, with both ends fixedly supported by these extension support plate portions 32, and extending parallel to the width direction W of the top plate 31; and a pair of driven rollers 35 that are positioned in the central portion between the pair of extension support plate portions 32 and are rotatably supported and attached to the pair of fixed rotating shafts 34, and rotate around these fixed rotating shafts 34.

[0029] Furthermore, a gripping fitting 36, formed by bending a reinforcing bar into a U-shape, for example, is attached to the top surface of the top plate 31 of the upper base portion 33 in an upright position by joining its lower end to the top plate 31 by welding or the like. By gripping the gripping fitting 36, it becomes easier to connect the upper divided weight 30 to the lower divided weight 20 by overlapping it on top of the lower divided weight 20, with the PC steel strand 4 sandwiched between the clamping groove 25a of the drive roller 25 of the lower divided weight 20 and the clamping groove 35a of the pair of driven rollers 35 of the upper divided weight 30.

[0030] The pair of extended support plate sections 32 of the upper base section 33 are made of horizontally elongated rectangular metal plate members and are positioned directly above each of the pair of upright support plate sections 23 that rise from the base section 22 of the lower divided weight section 20 when the upper divided weight section 30 is connected so as to overlap the lower divided weight section 20. Upper fastening flanges 42, which have through holes 42a formed in them and constitute the connecting pressing means 40 described later, are provided on both sides of the extended support plate section 32 in the direction of the long side, extending laterally and straddling the pair of extended support plate sections 32. Furthermore, a pair of fixed rotating shafts 34, which are cylindrical rods, are mounted with their ends supported on both sides by these pair of extended support plate sections 32, as described above, and are arranged parallel to the width direction W of the top plate 31. In the portion between these pair of extended support plate sections 32, driven rollers 35 are mounted, as described above, so as to be rotatably supported on the pair of fixed rotating shafts 34 via bearings or the like.

[0031] Each of the pair of driven rollers 35 is made of a urethane rubber roller member, preferably having a clamping groove 35a with an arc-shaped cross-section formed on its outer circumference. Because each driven roller 35 is made of a urethane rubber roller member, it deforms along the outer shape of the PC steel strand 4, making it easier for the driven roller 35 to adhere closely to the PC steel strand 4, thereby more effectively preventing the PC steel strand 4 from slipping. Preferably, the radius of curvature of the clamping groove 35a with an arc-shaped cross-section is larger than the radius of curvature of the outer surface of the PC steel strand 4 being fed out.

[0032] The pair of driven rollers 35 rotate around a fixed rotation axis 34, which is arranged parallel to the drive rotation axis 24 of the drive roller 25, when the upper divided weight body 30 is connected so as to overlap the lower divided weight body 20. The pair of driven rollers 35 are positioned on both sides of the drive roller 25, above it, in the longitudinal direction L of the curved mounting base portion 21 and the top plate 31. As a result, by rotating the drive roller 25 with the PC steel strand 4 sandwiched in the gap between the drive roller 25 and the pair of driven rollers 35, the sandwiched PC steel strand 4 can be fed in the feeding direction X toward the notch portion 53 facing the end opening 3a of the sheath pipe 3 (see Figure 2). When the PC steel strand 4 is fed out, the PC steel strand 4 is guided by the driven roller 35 on the downstream side in the feeding direction X so as not to bend upward, and preferably is fed out in a straight line or while curving downward, so that the PC steel strand 4 can be inserted more smoothly toward the end opening 3a of the sheath pipe 3 which is preferably facing the notch 53 formed in the segment ring 52 via the X anchor 61.

[0033] The connecting and pressing means 40, which together with the lower divided weight body 20 and the upper divided weight body 30 constitute the PC steel wire insertion device 10, preferably consists of a lower fastening flange 41 having screw holes 41a, which is provided on both sides of the lower divided weight body 20 in the PC steel wire feed direction X, and an upper fastening flange 42 having through holes 42a, which is provided on both sides of the upper divided weight body 30 in the PC steel wire feed direction X, respectively, and fastened between them, as shown in Figures 3(a) and 4(a).

[0034] In other words, the connecting and pressing means 40, consisting of a long bolt member 43a and a nut member 43b, is configured such that, for example, the upper male threaded portion of the long bolt member 43a is inserted through the through hole 42a of the upper fastening flange 42, and the lower male threaded portion is screwed into the screw hole 41a of the lower fastening flange 41. The nut member 43b is then tightened from above onto the portion of the upper male threaded portion that protrudes above the upper fastening flange 42, thereby fastening it to the upper fastening flange 42. This makes it possible to connect the lower divided weight body 20 and the upper divided weight body 30 as a single unit by stacking them vertically, with the PC steel strand 4, which is inserted in the gap between the drive roller 25 and the pair of driven rollers 35, sandwiched between these rollers 25 and 35. Furthermore, by increasing or decreasing the amount of tightening by the nut member 43b, for example, the pressing force when the PC steel strand 4 is sandwiched between the drive roller 25 and the pair of driven rollers 35 can be adjusted as appropriate. The connecting and pressing means 40 does not necessarily have to consist of a long bolt member 43a and a nut member 43b; it may also be a one-touch connecting and pressing means consisting of a clamp member, a buckle member, or the like.

[0035] To perform the work of inserting PC steel wires 4 into sheath pipes 3 embedded in the circumferential direction of segment rings 52, using the PC steel wire insertion device 10 for shield tunneling with the above-described configuration, in the working space inside the shield tunnel 50, with the arc-shaped inner surface of the segment rings 52 serving as a working platform, the PC steel wire insertion device 10 is suspended so as to be able to move up and down from an electric winch 57 attached to a support frame 56 made of, for example, I-beams 56a, which is supported by the shield tunneling machine 55 and installed inside it.

[0036] Here, the support frame 56 is composed of a pair of I-beams 56a positioned in the central part of the circular hollow cross-section of the skin plate 55a, which is the outer shell of the shield tunneling machine 55. The support frame 56, including the pair of I-beams 56a, is provided in a state where it extends out to the rear of the skin plate 55a by being supported by a support member (not shown) that supports, for example, a known erector device 60 (see Figure 1) installed inside the shield tunneling machine 55 to assemble the segment rings 52, with one end joined to it. This allows the support frame 56 to advance in the excavation direction as a whole, together with the skin plate 55a and the erector device 60, as the shield tunneling machine 55 excavates. Preferably, a known suspension frame 62 is fixed to the support frame 56 so as to be erected between the pair of I-beams 56a in the working area of ​​the rear end of the skin plate 55a in the excavation direction where the erector device 60 is located, and an electric winch 57 is attached to the central part of this suspension frame 62.

[0037] In this embodiment, for example, the locking tip of the linear member 57a extending downward from the electric winch 57 is preferably locked into the suspension hole 28 in the upper central part of the motor fixing plate 27, thereby enabling the PC steel wire insertion device 10 to be suspended from the suspension frame 62 in a balanced manner while being able to be raised and lowered by the electric winch 57.

[0038] Furthermore, in this embodiment, with the PC steel wire insertion device 10 suspended from the suspension frame 62, for example as shown in Figure 7, the PC steel wire insertion device 10 can be easily and smoothly installed at a predetermined position on the inner circumferential surface of the segment ring 52, with the length L of the curved mounting bottom surface 21 facing the circumferential direction, by manually lowering the PC steel wire insertion device 10 while pushing it in a predetermined direction. Furthermore, as shown in Figure 5, if the PC steel wire insertion device 10 is to be installed in the area between the lowest part of the circular cross-section of the segment ring 52 and one side end, a considerable distance to the side from the portion directly below the electric winch 57, it is considered difficult to lift it up manually by a worker. Therefore, by lifting it up with a lever block (registered trademark) 58 locked to the I-beam 56a on the side of the electric winch 57 and then lowering it, it becomes possible to easily and smoothly install the PC steel wire insertion device 10 in a predetermined position in the area between the lowest part of the circular cross-section of the segment ring 52 and one side end, a distance to the side from the portion directly below the electric winch 57 on the inner circumferential surface of the segment ring 52, with the length L of the curved mounting base portion 21 facing the circumferential direction.

[0039] As shown in Figure 2, the PC steel wire insertion device 10 is installed at the lowest position of the circular cross-section of the segment ring 52, with the feeding direction X, which is the length direction L of the curved mounting base portion 21, facing the circumferential direction of the segment ring 52. To insert the PC steel strand 4 into the sheath pipe 3 through the notch portion 53 formed in the region between the lowest position of the circular cross-section of the segment ring 52 and one side end, the PC steel strand 4 is sandwiched in the gap between the drive roller 25 of the lower divided weight body 20 and the pair of driven rollers 35 of the upper divided weight body 30 in the installed PC steel wire insertion device 10. The operation of sandwiching the PC steel strand 4 is performed, for example, by loosening the tightening of the nut member 43b of the connecting pressing means 40 and lifting the upper divided weight body 30, thereby widening the gap between the drive roller 25 of the lower divided weight body 20 and the pair of driven rollers 35 of the upper divided weight body 30. The PC steel strand 4 is inserted through the widened gap and positioned so that it is sandwiched between the V-shaped clamping groove 25a of the drive roller 25 and the arc-shaped clamping groove 35a of the pair of driven rollers 35. Then, the lifted upper divided weight body 30 is placed on top of the lower divided weight body 20 and the nut member 43b is tightened, making it possible to sandwich the PC steel strand 4 between the clamping groove 25a of the drive roller 25 and the clamping groove 35a of the pair of driven rollers 35 with a predetermined pressing force.

[0040] Once the PC steel strand 4 is sandwiched between the drive roller 25 and a pair of driven rollers 35 of the PC steel wire insertion device 10, the hydraulic motor 26 is driven to rotate the drive roller 25. This allows the sandwiched PC steel strand 4 to be fed towards the X anchor 61, a known anchoring fitting that connects to the end opening 3a of the sheath pipe 3 embedded in the segment ring 52, which is fixed integrally in the concrete of the intermediate anchor base 53a in the notch 53 formed in the region between the lowest part of the circular cross-section of the segment ring 52 and one side end.

[0041] Here, the notch 53 formed on the inner circumferential surface of the segment ring 52 has a pair of ship-bottom shaped notches 53b that extend circumferentially along the inner circumferential surface of the segment ring 52, on both sides of the intermediate anchor base 53a to which the X anchor 61 is fixed. In addition, the X anchor 61 is embedded and fixed in the concrete of the intermediate anchor base 53a with one of each pair of open end faces facing the rear end face of the ship-bottom shaped notches 53b, and the other of each pair of open end faces connected to the end opening 3a of the sheath pipe 3 embedded in the segment ring 52.

[0042] The PC steel strands 4, fed from the PC steel wire insertion device 10 toward the notch 53, are inserted into one open end face of the X anchor 61, which is positioned facing one of the bottom-shaped notches 53b of the notch 53. After being further pushed in, they are inserted into the sheath pipe 3, which is connected to the other open end face of the X anchor 61. The PC steel strands 4 inserted into the sheath pipe 3 are then inserted along the sheath pipe 3 embedded in the segment ring 52, making one full rotation in the circumferential direction of the segment ring 52. After this, their tip is pushed out from the open end face of the X anchor 61 facing the other bottom-shaped notch 53b, extending outwards and protruding toward the other bottom-shaped notch 53b.

[0043] Subsequently, the tip of the PC steel strand 4 protruding from the other bottom-shaped notch 53b is pulled along with the base end of the PC steel strand 4 that remains uninserted into the X anchor 61 in the other bottom-shaped notch 53b using a known pulling device such as a center hole jack. This introduces circumferential prestress (pre-compression force) to the segment ring 52, and the known anchoring fixture is then used to anchor it to the X anchor 61, which is a known anchoring fitting. This makes it possible to effectively reinforce the shield tunnel 50 so that it can withstand circumferential tensile loads due to internal water pressure, for example, when the shield tunnel 50 is used as a temporary water storage facility for rainwater, by introducing prestress in the circumferential direction of the segment ring 52.

[0044] As a result, in this embodiment, for example, using the PC steel wire insertion device 10 for internal water pressure resistant shield tunneling, it becomes possible to efficiently and smoothly insert PC steel strands 4, which are PC steel wires, into the sheath pipes 3 that are continuously embedded in the segment ring 52 in the circumferential direction within the shield tunnel 50 with less effort. Furthermore, by introducing prestress in the circumferential direction of the segment ring 52, it becomes possible to effectively reinforce the shield tunnel 50 so that it can withstand circumferential tensile loads such as those caused by internal water pressure.

[0045] Furthermore, in this embodiment, as shown in Figure 6, for example, each segment ring 52 assembled using concrete segments 51 has a plurality of sheath pipes 3, with four rows of sheath pipes 3 extending continuously in the circumferential direction, arranged in multiple rows at predetermined intervals in the axial direction of the tunnel 50, from the tunnel entrance side to the tunnel face side. The notches 53 into which the PC steel wire strands 4 are inserted are, for example, positioned as a first position for the first and third rows of sheath pipes 3 from the tunnel entrance side, preferably at the bottom of the circular cross-section of the segment ring 52, and positioned as a second position for the second and fourth rows of sheath pipes 3 from the tunnel entrance side, preferably between the bottom of the circular cross-section of the segment ring 52 and one side end, and are arranged alternately in an alternating pattern with circumferential positioning.

[0046] For a segment ring 52 in which multiple rows and multiple locations of sheath tubes 3 and notches 53 are arranged in this manner, it becomes possible to efficiently insert PC steel strands 4, which are PC steel wires, into each sheath tube 3 by following the procedure below.

[0047] In other words, in this embodiment, the hollow interior of the rear end portion of the circular cross-section skin plate 55a constituting the shield tunneling machine 55 is used as the working area. As shown in Figure 1, the PC steel wire insertion device 10 is lifted to the central portion of the skin plate 55a by an electric winch 57 attached to the central portion of the suspension frame 62. The erector device 60 is rotated circumferentially, and the segment gripping portion 60a is moved radially, while one segment ring 52 is assembled using multiple concrete segments 51. After one ring is assembled using the segment ring 52, the erector device 60 is preferably rotated circumferentially to retract the segment gripping portion 60a upward, and the PC steel wire insertion device 10, which had been lifted to the central portion of the skin plate 55a, is lowered. Then, for example, the PC steel wire insertion device 10 is used to insert the PC steel strands 4 into the first row of sheath pipes 3 on the tunnel entrance side.

[0048] Since the notch 53 in the first row of sheath tubes 3 is preferably located at the lowest point of the circular cross-section of the segment ring 52 (see Figure 6), as shown in Figure 5, the PC steel wire insertion device 10 can be raised to the area between the lowest point of the circular cross-section of the segment ring 52 and one side end using a lever block (registered trademark) 58 that is locked to the I-beam 56a on the side of the electric winch 57, and then lowered while finely adjusting the position mainly in the front-rear direction by a worker, and adjusting the orientation so that the feeding direction X matches the circumferential direction of the segment ring 52, the PC steel wire insertion device 10 can be installed in the area between one side end and the lowest point of the circular cross-section of the segment ring 52, with the curved mounting bottom surface 21 of the PC steel wire insertion device 10 in close contact with the inner circumferential surface that curves in the circumferential direction of the segment ring 52.

[0049] Subsequently, the nut member 43b of the connecting pressing means 40 is loosened, and with the upper divided weight body 30 slightly lifted, the PC steel strand 4 is passed through the gap between the drive roller 25 and the pair of driven rollers 35. Then, the nut member 43b is tightened again to sandwich the PC steel strand 4 between them with a predetermined pressing force, and the hydraulic motor 26 is rotated to feed and insert the PC steel strand 4 into the sheath pipe 3 which is continuously embedded in the segment ring 52 in the circumferential direction. Once the PC steel strand 4 is inserted, the PC steel strand 4 inserted into the sheath pipe 3 is pulled at the notch 53 using a known pulling device, thereby introducing circumferential prestress (pre-compression force) to the segment ring 52 as described above, and the end of the PC steel strand 4 can be fixed to the X anchor 61 placed in the notch 53 via a fixing jig.

[0050] After inserting the PC steel strands 4 into the first row of sheath pipes 3 and fixing their ends while applying tensile force, the PC steel wire insertion device 10 is moved again to the lowest point of the circular cross-section of the segment ring 52 and suspended, for example, using a lever block (registered trademark) 58 and an electric winch 57. Then, preferably by manually pushing it out, the PC steel wire insertion device 10 is lowered while making fine adjustments to the axial position of the tunnel 50. This allows the PC steel wire insertion device 10 to be installed on the extension of the second row of sheath pipes 3, preferably at the lowest point of the circular cross-section of the segment ring 52, with the curved mounting base 21 in close contact with the curved inner surface of the segment ring 52. Since the notch 53 in the second row of sheath tubes 3 is preferably located in the region between one side end and the bottom of the circular cross-section of the segment ring 52, the PC steel strand 4 can be inserted into the sheath tube 3, which is continuously embedded in the segment ring 52 in the circumferential direction, through the notch 53 located in the region between one side end and the bottom of the circular cross-section of the segment ring 52, by rotating the hydraulic motor 26 with the PC steel strand 4 sandwiched between the drive roller 25 and the pair of driven rollers 35 of the installed PC steel wire insertion device 10. Furthermore, while applying tensile force, the end of the inserted PC steel strand 4 can be fixed to the X anchor 61 located in the notch 53 via a fixing jig.

[0051] After inserting the PC steel strands 4 into the second row of sheath pipes 3 and fixing the ends of the PC steel strands 4 to which tensile force has been applied, the PC steel wire insertion device 10 is moved again to the 6 o'clock position and suspended using, for example, a lever block (registered trademark) 58 or an electric winch 57. Then, by manual operation by workers and using the lever block (registered trademark) 58 or electric winch 57, the device is pulled up again to the area between one side end of the circular cross-section of the segment ring 52 and the lowest part. From this state, for example, by repeating the same operation as described above, the PC steel strands 4 can be inserted into the third and fourth rows of sheath pipes 3, tensile force can be applied, and the ends of the PC steel strands 4 to which tensile force has been applied are fixed in the notches 53, thereby introducing circumferential prestress (pre-compression force) to the segment ring 52.

[0052] Therefore, the PC steel wire insertion method in the shield tunneling method of this embodiment is a method for inserting PC steel wires 4 into embedded sheath pipes 3 using a PC steel wire insertion device 10, in which, as a shield tunneling method, a segment ring 52 is assembled using concrete segments 51 in which sheath pipes 3 are embedded in advance, and then PC steel wires 4 are inserted through notches 53 provided in the assembled segment ring 52 and tensioned and fixed to introduce prestress in the circumferential direction of the segment ring 52. Furthermore, the PC steel wire insertion device 10 is composed of a lower segmented weight body 20 and an upper segmented weight body 30, and when placed on the segment ring 52, it has a considerable weight that allows it to obtain the reaction force when inserting the PC steel wire 4 by its own weight, and the lower segmented weight body 20 has a curved mounting bottom portion 21 that is curved with a radius of curvature similar to that of the inner circumferential surface of the segment ring 52.The PC steel wire insertion method in the shield tunneling method of this embodiment involves an installation step in which the PC steel wire insertion device 10 is suspended by an electric winch 57, which is a lifting device installed in the central part of the circular hollow cross-section of the shield tunneling machine 55, and then lowered while positioning the suspended PC steel wire insertion device 10 so that the feeding direction X matches the circumferential direction of the row of sheath pipes 3 in which the notches 53 are arranged, and the PC steel wire insertion device 10 is installed on the inner circumferential surface of the segment ring 52, and the PC steel wire 4 is sandwiched between the drive roller 25 and driven roller 35 of the installed PC steel wire insertion device 10 and the hydraulic motor 26 is rotated. The system is configured to include an insertion step in which the PC steel wire 4 is fed towards the sheath pipe 3 with its end opening 3a facing the notch 53 and inserted into the sheath pipe 3, and a reinstallation step in which the PC steel wire insertion device 10, after the PC steel wire 4 has been inserted into the sheath pipe 3, is lifted by the lifting device 57, the lifted PC steel wire insertion device 10 is suspended by the lifting device 57, the suspended PC steel wire insertion device 10 is lowered while being positioned, and the PC steel wire insertion device 10 is reinstalled on the inner surface of the segment ring 52 so that the feeding direction X matches the circumferential direction of the next row of sheath pipes 3 where the notch 53 is located.

[0053] It should be noted that the present invention is not limited to the above embodiments and can be modified in various ways. For example, it is not necessarily required that urethane rubber be attached to the curved mounting bottom surface, and the clamping groove on the outer circumference of the drive roller does not necessarily need to have a V-shaped cross-section. The driven roller does not have to be made of a roller member made of urethane rubber. [Explanation of Symbols]

[0054] 3. Sheath tube 3a End opening 4PC steel strands (PC steel wire) 10 PC steel wire insertion device 20 Lower split weight body 21 Curved mounting base 21a Bottom 21b Urethane rubber 22 Base 22a Support plate 22b Base Plate 23 Standing support plate section 24 Drive Rotating Shaft 25 drive rollers 25a, 35a pinch groove 26 Hydraulic motor 26a Motor Rotation Shaft 26b Joint flange 27 Motor fixing plate section 27a Fixed bottom plate part 28 Hanging holes 29 Chain Coupling 30 Upper split weight body 31 Top plate 32 Extension support plate part 33 Upper base 34 Fixed Rotating Shaft 35 Driven roller 36 Gripping hardware 40 Connecting pressing means 41 Lower clamping flange 41a Screw hole 42 Upper fastening flange 42a through hole 43a Long bolt member 43b Nut component 50 Shield Tunnel 51 segments 52 Segment Ring 53 Notch 53a Intermediate anchor base 53b Bottom shape notch 55 Shield tunneling machine 55a Skin Plate 56 Support frame 56a I-beam 57 Electric winch (lifting device) 57a, 58a Linear members 58 Lever Block (Registered Trademark) 60 Erecta equipment 61 X-Anchor 62 Hanging Frames W (width direction) L (Length direction) X Sending direction

Claims

1. In a shield tunneling method in which a segment ring is assembled using concrete segments with pre-embedded sheath pipes, and then PC steel wires are inserted through notches in the assembled segment ring and tensioned to introduce prestress in the circumferential direction of the segment ring, the present invention relates to a PC steel wire insertion method using a PC steel wire insertion device for inserting the PC steel wires into the embedded sheath pipes, The sheath tubes are embedded in the segment ring in a continuous manner in the circumferential direction and are arranged in multiple rows at predetermined intervals in the axial direction. The PC steel wire insertion device comprises a lower segmented weight and an upper segmented weight, and when placed on the segment ring, it has a considerable weight that allows it to obtain the reaction force when inserting the PC steel wire through its own weight, and the lower segmented weight has a curved mounting bottom portion that is curved with a radius of curvature similar to that of the inner circumferential surface of the segment ring. The installation process involves suspending the PC steel wire insertion device from a state where it is suspended by a lifting device installed in the central part of the hollow cross-section of the shield tunneling machine, lowering the suspended PC steel wire insertion device while positioning it, and installing the PC steel wire insertion device on the inner surface of the segment ring so that the feeding direction matches the circumferential direction of the row of sheath pipes in which the notches are arranged, and then inserting the PC steel wire between the drive roller and driven roller of the installed PC steel wire insertion device and rotating the motor to insert the PC steel wire into the sheath pipe with its end opening facing the notch. A method for inserting PC steel wires in a shield tunnel construction method, comprising: an insertion step of sending the PC steel wire towards and inserting it into the sheath pipe; and a reinstallation step of lifting the PC steel wire insertion device after inserting the PC steel wire into the sheath pipe using the lifting device, lowering the lifted PC steel wire insertion device using the lifting device, lowering the suspended PC steel wire insertion device while positioning it, and reinstalling the PC steel wire insertion device on the inner surface of the segment ring so that the sending direction matches the circumferential direction of the next row of sheath pipes where the notches are arranged.

2. The method for inserting PC steel wires in a shield tunneling method according to claim 1, wherein the notches provided in each row of the sheath pipes, which are arranged in a plurality of rows at predetermined intervals in the axial direction, are alternately arranged at a first position and a second position in the circumferential direction with their positions shifted in the circumferential direction.

3. The method for inserting PC steel wires in a shield tunneling method according to claim 2, wherein the first position in the circumferential direction is the lowest position of the circular cross-section of the segment ring, and the second position is a position between one side end of the circular cross-section of the segment ring and the first position.

4. A method for inserting PC steel wires in a shield tunnel construction method according to claim 1 or 2, wherein the erector device with the assembled segment rings is rotated in the circumferential direction to retract the segment gripping portion upwards before the method is performed.

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