Steel pipe connecting jig

Abstract

To reduce a workload of a worker when connecting steel pipes driven into the ground in a straight line by a push-fit method in an auxiliary method for tunnel construction.SOLUTION: A movable steel pipe receiver 33 of a steel pipe connection jig 30 is provided in a guide cell 23 of a driving drill jumbo 20. The movable steel pipe receiver 33 is advanced and retreated by an advance / retract drive unit 50. The movable steel pipe receiver 33 is provided with a receiving portion 33c that receives a steel pipe 10B to be spliced, and a holding portion 32. The holding portion 32 is advanced together with the movable steel pipe receiver 33 when advanced by the advance / retract drive unit 50, while being kept immovable relative to the steel pipe 10B, and is released from the steel pipe 10B after being pushed in and fitted by the advance.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a jig for linearly connecting steel pipes to each other in an auxiliary construction method for mountain tunnel construction, and particularly relates to a steel pipe connecting jig applied to steel pipes connected by press-fitting instead of screw jointing.

Background Art

[0002] When constructing a mountain tunnel by the NATM (New Austrian Tunneling Method), auxiliary construction methods such as the AGF (All Ground Fasting) method and face bolt method are sometimes implemented to reinforce the natural ground during excavation. In this type of auxiliary construction method, steel pipes are driven into the natural ground using a machine such as a drill jumbo, for example. A plurality of steel pipes are sequentially connected in a straight line to achieve a long length. Generally, steel pipes are connected to each other by screw jointing (see Patent Document 1, etc.). The newly added steel pipe is mounted on the guide cell of the drill jumbo and arranged to be aligned straight with the already driven steel pipe. Thereafter, a worker uses a tool such as a pipe wrench or chain tong to manually pull out and rotate the added steel pipe, thereby performing screw jointing with the end of the already driven steel pipe. This screw jointing method requires rotation of the additional steel pipe, which is time-consuming. In addition, the screw joint structurally becomes a weak point.

[0003] Accordingly, instead of screw jointing, connecting steel pipes to each other by press-fitting has been proposed (see Patent Document 2, etc.). An end portion of one steel pipe in the press-fitting method is formed with a plurality of locking claws arranged in an annular shape. An end portion of the other steel pipe is formed with an annular locking groove. When the additional steel pipe is pushed straight along the pipe axis toward the already driven steel pipe, the locking claws are elastically deformed and fit into the locking groove to be locked. Thereby, steel pipes can be connected to each other with one touch only by linear movement.

Prior Art Literature

Patent Literature

[0004] [Patent Document 1] Japanese Patent Publication No. 2016-12144 [Patent Document 2] Japanese Patent Publication No. 2020-111880 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] However, in the aforementioned push-fit method, the steel pipe on the extension side must be strongly pushed in to elastically deform the locking claw, requiring a force of approximately 1 kN. Therefore, even with tools such as pipe wrenches and chain tongs, the workload was excessive when using only manual force. In addition, since the work is usually performed on elevated work platforms such as the man gauge of a drill jumbo, the footing is often poor, making it difficult to get a firm footing and thus difficult to obtain reaction force, further complicating the working conditions. It was also not easy to join the pipes using the existing mechanism of the drill jumbo as is. In view of these circumstances, the present invention aims to reduce the workload on workers when connecting steel pipes driven into the ground in a straight line using a push-fitting method in an auxiliary construction method for tunnel construction. [Means for solving the problem]

[0006] To solve the aforementioned problem, the inventor conceived of using a steel pipe connecting jig to apply a pushing force to the extension steel pipe on behalf of the worker. The present invention is based on such an idea and is a steel pipe connecting jig used in a tunnel auxiliary construction method in which multiple steel pipes connected in a straight line by push-fitting are driven into the ground, A fixed steel pipe holder is fixed to the tip of the guide cell of the drill jumbo for driving, and has a sliding support portion that can slidly receive the steel pipe to be extended in the pipe axis direction, A holding part is provided in front of the fixed steel pipe support so as to be movable back and forth, and holds the steel pipe to be extended in a way that is not relative to it and can be released, A reciprocating drive unit that moves the holding part forward and backward, It is characterized by having the following features.

[0007] Furthermore, the present invention relates to a steel pipe connecting jig used in a tunnel auxiliary construction method for driving multiple steel pipes, which are connected in a straight line by push-fitting, into the ground, A movable steel pipe support is provided in the guide cell of the aforementioned drill jumbo for driving, The movable steel pipe support is driven by a moving mechanism, The movable steel pipe support is provided with a receiving portion for receiving the steel pipe to be extended and a holding portion, wherein the holding portion is moved forward together with the movable steel pipe support when the forward / backward drive unit moves forward while maintaining a state in which it is immovable relative to the steel pipe to be extended, and is separated from the steel pipe after the push-fit is achieved by the forward movement. The holding portion may be provided integrally with the movable steel pipe support. Preferably, the holding portion includes a clamp for clamping the steel pipe to be extended. [Effects of the Invention]

[0008] According to the present invention, in an auxiliary construction method for tunnel construction, the workload on workers can be reduced when connecting steel pipes driven into the ground in a straight line using a push-fitting method. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a side view of a drill jumbo equipped with a steel pipe connecting jig according to one embodiment of the present invention. [Figure 2] Figure 2(a) is a plan view showing the steel pipe connecting jig in the ready-to-press state. Figure 2(b) is a side view of the steel pipe connecting jig in the ready-to-press state. [Figure 3] Figure 3 is an exploded perspective view of the steel pipe connecting jig. [Figure 4] Figure 4(a) is a side view showing the steel pipe connecting jig in the pushed-in state. Figure 4(b) is a side view showing the steel pipe connecting jig in the retracted state. [Modes for carrying out the invention]

[0010] One embodiment of the present invention will be described below with reference to the drawings. Figure 1 shows Tunnel 1 under construction using the NATM method. The ground 2 is being excavated to construct Tunnel 1. During construction, as an auxiliary method for reinforcing the ground, for example, using the AGF method, numerous (only one is shown in the figure) long pre-support steel pipes 9 (ground reinforcement pipes) are driven into the ground ahead of the tunnel face. A drill jumbo 20 is used for driving them in. Each long pre-support steel pipe 9 is composed of multiple (for example, about four) steel pipes 10. These steel pipes 10 are connected in a straight line.

[0011] As shown in Figure 1, one-touch connection parts 11 are formed at the end 10e of the leading end (left in Figure 1) and the end 10f of the rear end (right in Figure 1) of two adjacent steel pipes 10. As shown in Figure 2(a), the one-touch connection part 11 includes an annular locking groove 12 formed on the inner circumferential surface of the end 10e of the leading end steel pipe and a locking claw 13 formed on the end 10f of the rear end steel pipe. For example, the locking groove 12 is formed in a wedge-shaped concave cross-section. The locking claw 13 is formed in a wedge-shaped convex cross-section (see Patent Document 2). The locking claw 13 is annular and is divided into a plurality of locking claw portions 13a by a slit 14. The locking claw portions 13a and thus the locking claw 13 are locked into the locking groove 12. The tip 10f of the rear end of the steel pipe is inserted into the end 10e of the front end of the steel pipe, causing the locking claw 13 to fit into the locking groove 12.

[0012] The end portion 10e and the tip portion 10f of the steel pipe 10, including the locking groove 12 and the locking claw 13, are preferably made of high-tensile steel. The intermediate portion of the steel pipe 10, excluding the end portion 10e and the tip portion 10f, may be made of ordinary steel.

[0013] Note that a drilling rod 24 (illustrated only in FIG. 1) is inserted through the interior of the preceding steel pipe 9. A drilling bit 25 is provided at the tip of the drilling rod 24. The rear end of the drilling rod 24 is connected to a drifter 26 on a guide cell 23 of a drill jumbo 20.

[0014] As shown in FIG. 1, a steel pipe connection jig 30 is prepared for connecting the steel pipes 10 to each other. The steel pipe connection jig 30 is incorporated in the drill jumbo 20. A boom 22 extends from a machine body 21 of the drill jumbo 20, and a guide cell 23 is provided at the tip of the boom 22. The steel pipe connection jig 30 is attached to the tip of the guide cell 23. Preferably, the steel pipe connection jig 30 is attachable to and detachable from the guide cell 23.

[0015] As shown in FIG. 2(a) and FIG. 2(b), the steel pipe connection jig 30 includes a fixed steel pipe receiver 31, a movable steel pipe receiver 33, a telescopic guide 40 (guide member), and an advancing / retreating drive unit 50. The fixed steel pipe receiver 31 is formed of a thick steel plate. The fixed steel pipe receiver 31 is oriented so as to be orthogonal to the longitudinal direction (front-rear direction) of the guide cell 23, and is abutted against and fixed to the distal end surface of the guide cell 23. As shown in FIG. 3, the fixed steel pipe receiver 31 has a pair of convex plate portions 31a and 31b. The convex plate portions 31a and 31b protrude upward from both left and right side portions of the bottom of the fixed steel pipe receiver 31. The upper end heights of the left and right convex plate portions 31a and 31b are different from each other. A slide receiving portion 31c is formed between these convex plate portions 31a and 31b. The slide receiving portion 31c penetrates the fixed steel pipe receiver 31 in the front-rear direction and forms a U-shaped hole open at the upper end of the fixed steel pipe receiver 31, and receives the steel pipe 10B to be added so as to be slidable in the longitudinal direction of the guide cell 23. The pipe axis direction of the steel pipe 10B is oriented in the longitudinal direction of the guide cell 23. A centralizer for steel pipes provided in the guide cell 23 may be used as the fixed steel pipe receiver 31.

[0016] As shown in Fig. 3, a telescopic guide 40 protrudes forward from the tip end of the guide cell 23. The telescopic guide 40 includes a cylindrical fixed guide part 41 and a cylindrical movable guide part 42 that is one size smaller than the fixed guide part 41, and has a double cylinder structure. The axial direction of the telescopic guide 40 is oriented toward the longitudinal direction of the guide cell 23. The cross-sections of the fixed guide part 41 and the movable guide part 42 are quadrilateral, but are not limited thereto and may be circular. The rear end portion of the fixed guide part 41 is fixed to a fixed steel pipe receiver 31. As shown in Fig. 2(b) and Fig. 4(a), the movable guide part 42 is accommodated inside the fixed guide part 41 so as to be capable of advancing and retracting in the axial direction. As the movable guide part 42 advances and retracts, the telescopic guide 40 expands and contracts in the axial direction (front-rear direction).

[0017] A movable steel pipe receiver 33 and a clamp 34 are arranged in front of the fixed steel pipe receiver 31 (to the left in Fig. 2(b)) via the telescopic guide 40. The movable steel pipe receiver 33 can advance and retract in the front-rear direction through expansion and contraction of the telescopic guide 40. Furthermore, the clamp 34 is included in a holding part 32 that holds the steel pipe 10B in a releasable manner and prohibits relative movement of the steel pipe 10B with respect to the clamp 34.

[0018] More specifically, as shown in Fig. 2(a), similar to the fixed steel pipe receiver 31, the movable steel pipe receiver 33 is formed of a thick steel plate. The movable steel pipe receiver 33 is oriented so as to be orthogonal to the longitudinal direction (front-rear direction) of the guide cell 23, and is fixed by being abutted against the tip end surface of the movable guide part 42. As shown in Fig. 3, the movable steel pipe receiver 33 has a pair of convex plate parts 33a, 33b. The convex plate parts 33a, 33b protrude upward from both left and right side portions of the bottom part of the movable steel pipe receiver 33. The heights of the upper ends of the left and right convex plate parts 33a, 33b are different from each other, and furthermore, the height arrangement is reversed left-right relative to the convex plate parts 31a, 31b of the fixed steel pipe receiver 31. A receiving part 33c is formed between the convex plate parts 33a, 33b. The receiving part 33c penetrates the movable steel pipe receiver 33 in the front-rear direction and has a U-shaped hole shape reaching the upper end of the movable steel pipe receiver 33. The receiving part 33c receives the steel pipe 10B. The movable steel pipe receiver 33 and the fixed steel pipe receiver 31 are opposed to each other in the front-rear direction, and are connected via the telescopic guide 40 so as to be capable of approaching and separating from each other.

[0019] As shown in Figures 2(a) and (b), a clamp 34 is positioned in front of the movable steel pipe support 33. Preferably, the clamp 34 abuts against the front surface of the movable steel pipe support 33. The clamp 34 is detachably attached to the outer circumference of the portion of the steel pipe 10B in front of the movable steel pipe support 33.

[0020] As shown by the solid line in Figure 3, the clamp 34 includes a pair of clamp members 34a and a tightening tool 34b. Each clamp member 34a is formed in a semicircular shape. The pair of clamp members 34a are rotatably connected to each other via a hinge 34c. As shown by the dashed line in Figure 3, these clamp members 34a clamp the steel pipe 10B from both sides. The ends of the clamp members 34a opposite the hinge 34c by 180 degrees are detachably connected by the tightening tool 34b. The tightening tool 34b includes, for example, a bolt. When the tightening tool 34b is tightened, the clamp 34 is fixed to the outer circumference of the steel pipe 10B. By loosening and removing the tightening tool 34b, the clamp 34 is separated from the steel pipe 10B.

[0021] As shown in Figure 2(a), the forward / backward drive unit 50 includes a pair of hydraulic cylinders 51. The pair of hydraulic cylinders 51 are arranged on both the left and right sides (up and down in Figure 2(a)) of the telescopic guide 40. The cylinder portion 52 of each hydraulic cylinder 51 is connected to and supported laterally by the guide cell 23. The tip of the piston rod 53 of the hydraulic cylinder 51 is connected directly to the movable steel pipe support 33 or via a bracket (not shown). Although not shown, some hydraulic hoses of the drill jumbo 20 are connected to the hydraulic cylinders 51. In this way, hydraulic driving force for the hydraulic cylinders 51 is supplied from the drill jumbo 20. The telescopic guide 40 extends and retracts, and the movable steel pipe support 33 moves forward and backward, due to the extension and retraction drive of the retraction and retraction drive unit 50, which consists of a pair of hydraulic cylinders 51.

[0022] The steel pipe connecting jig 30 is used as follows: <Casting process> As shown in Figure 1, the lead support steel pipe 9 is driven into the ground 2 by the drill jumbo 20. Driving is stopped before the last steel pipe 10A of the lead support steel pipe 9 is completely buried in the ground 2, leaving the end 10e protruding into the tunnel 1.

[0023] <Steel pipe installation process> Next, as shown in Figure 3, the steel pipe 10B to be extended is placed so as to straddle the movable steel pipe receiver 33 and the fixed steel pipe receiver 31 of the steel pipe connecting jig 30. The steel pipe connecting jig 30 is inserted into the receiving portion 33c of the movable steel pipe receiver 33 and supported, and also inserted into the sliding receiving portion 31c of the fixed steel pipe receiver 31 and supported. <Excavation rod extension process> Before or after the steel pipe installation process, the excavation rod 24 (Figure 1) is extended by the length of the steel pipe 10B.

[0024] <Clamping process> As shown in Figures 2(a) and 2(b), a clamp 34 is attached to the front portion of the movable steel pipe support 33 on the steel pipe 10B and clamped. The clamp 34 is fixed to the steel pipe 10B by sandwiching the steel pipe 10B from both sides with a pair of clamp members 34a and tightening the fastener 34b. Preferably, the clamp 34 is abutted against the front surface of the movable steel pipe support 33.

[0025] <Positioning Process> Next, as shown in Figures 2(a) and 2(b), the boom 22 of the drill jumbo 20 is operated to align the pipe axis of the steel pipe 10B with the pipe axis of the pre-installed support steel pipe 9, and to bring the tip 10f of the steel pipe 10B close to the end 10e of the preceding steel pipe 10A. Preferably, a worker A (not shown), separate from the operator of the drill jumbo 20, is positioned on the elevated work platform 27 near the planned connection point of the steel pipes 10A and 10B, and worker A confirms the positioning while performing the work.

[0026] <Pressing process> Next, the hydraulic cylinder 51 of the forward / backward drive unit 50 is extended to move the movable steel pipe support 33 forward. As a result, as shown in Figure 4(a), the clamp 34 that abuts against the movable steel pipe support 33 moves forward together with the movable steel pipe support 33, and the steel pipe 10B fixed to the clamp 34 moves forward. The steel pipe 10B slides on the slide support portion 31c. The telescopic guide 40 is extended.

[0027] The tip 10f of the advancing steel pipe 10B is pushed into the end 10e of the steel pipe 10A, and the locking claw 13 is elastically deformed and engages with the locking groove 12 to lock in place. As a result, the tip 10f of the steel pipe 10B is connected to the end 10e of the steel pipe 10A with a single touch, and the steel pipe 10B can be extended to the pre-supported steel pipe 9 while it is being poured. The forward / backward drive unit 50 provides the pushing force, eliminating the need for worker A to manually push. Therefore, worker A only needs to perform the positioning process. This significantly reduces the burden on worker A.

[0028] <Evacuation process> Subsequently, the steel pipe 10B is released from the clamp 34 by loosening the tightening device 34b. Preferably, the clamp 34 is removed from the steel pipe 10B. Furthermore, as shown in Figure 4(b), the movable steel pipe support 33 is retracted (retracted) and the telescopic guide 40 is retracted by contracting the hydraulic cylinder 51. At this time, the support portion 33c slides along the steel pipe 10B.

[0029] <Resuming the casting process> Next, the drifter 26 (Figure 1) is advanced along the guide cell 23 and connected to the end of the steel pipe 10B, and the driving of the pre-supported steel pipe 9 by the drill jumbo 20 is resumed. By retracting (storing) the movable steel pipe support 33 (Figure 4(b)), the steel pipe connection jig 30 can be prevented from becoming an obstacle to steel pipe driving. Therefore, when driving is resumed, only the clamp 34 needs to be removed, and it is not necessary to remove the entire steel pipe connection jig 30 from the guide cell 23.

[0030] The above operation is repeated for the number of steel pipes 10 that make up the support steel pipe 9. This allows the support steel pipe 9 of a predetermined length to be driven into the ground 2.

[0031] The present invention is not limited to the embodiments described above, and various modifications can be made. For example, the movable steel pipe support 33 may have an integrated clamp for fixing the steel pipe 10B. The receiving portion 33c of the movable steel pipe support 33 may be a clamp that clamps the steel pipe 10B in a releaseable manner. In this case, during the steel pipe installation process, when the steel pipe 10B to be extended is supported by the movable steel pipe support 33, the steel pipe 10B is clamped by the clamp integrated with the movable steel pipe support 33. Subsequently, the pushing process by the forward / backward drive unit 50 causes the movable steel pipe support 33 and its integrated clamp to move forward, so that the steel pipe 10B moves forward and connects with the steel pipe 10A. After that, during the retraction process, the clamp integrated with the movable steel pipe support 33 is loosened to release the clamp from the steel pipe 10B, and then the movable steel pipe support 33 and its integrated clamp are moved backward. The telescopic guide 40 may also have an integrated forward / backward drive unit 50. [Industrial applicability]

[0032] This invention is applicable to auxiliary construction methods for ground reinforcement in the construction of mountain tunnels. [Explanation of Symbols]

[0033] 1 Tunnel 2. Natural terrain 9. Long steel pipe with end support 10 Steel pipe 10B Steel pipe to be extended 10e terminal 10f tip 11 One-touch connection section 12. Stop groove 13 Locking claws 13a Locking claw portion 14 slits 20 Drill Jumbo 21 aircraft 22 Boom 23 Guide Cells 24 drilling rods 25 drilling bits 26 Drifter 30 Steel pipe connecting jig 31 Fixed steel pipe support 1c Slide receiver 32 Holding part 33 Mobile steel pipe support 33c Receiving part 34 Clamps 34a Clamp member 34b Tightening tool 34c Hinge 40 Telescopic Guide 50 Reverse drive unit 51 Hydraulic Cylinder 52 Cylinder section 53 Piston Rod

Claims

1. A steel pipe connecting jig used in a tunnel auxiliary construction method in which multiple steel pipes connected in a straight line by push-fitting are driven into the ground, A movable steel pipe support is provided in the guide cell of the aforementioned drill jumbo for driving, The movable steel pipe support is driven by a moving mechanism, A steel pipe connecting jig comprising, wherein the movable steel pipe receiver is provided with a receiving portion for receiving the steel pipe to be extended and a holding portion, the holding portion is moved forward together with the movable steel pipe receiver when the forward / backward drive unit moves forward while maintaining a state in which it is immovable relative to the steel pipe to be extended, and is separated from the steel pipe after the push-fit is achieved by the forward movement.

2. The steel pipe connecting jig according to claim 1, wherein the holding portion is provided integrally with the movable steel pipe support.

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