Rock bolt installation method

Abstract

To provide a rock bolt construction method capable of smoothly and accurately performing rock bolt driving work and preventing accidental dropping of a washer.SOLUTION: A rock bolt construction method comprises a washer holding means installation step of installing washer holding means 8 on a tip side of a guide 34 for holding a washer 9 attached to a rear end of a rock bolt 2, a washer holding step of holding the washer in washer holding means, a rock bolt positioning step of passing a tip end of the rock bolt through a central through hole 90 of the washer 9 held by the washer holding means, a rock bolt driving step of bringing the washer held by the washer holding means close to a wall surface W around a driving hole H, and driving the rock bolt into the driving hole, and a washer installation step of installing the washer so as to support the wall surface W of a tunnel cavity T by removing the washer from the washer holding means and leaving the washer at the rear end of the rock bolt after driving the rock bolt.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for constructing a rock bolt by driving a rock bolt from a tunnel cavity into the natural ground.

Background Art

[0002] Conventionally, in the method for constructing a rock bolt, after forming a driving hole for driving a rock bolt from a tunnel cavity into the natural ground, a rock drill (drifter) is provided on a guide provided at the tip side of the boom of a face drilling machine called a drill jumbo (registered trademark) or the like so as to be movable along the extension direction of the guide, and the rear end portion of the rock bolt is attached to the tip side of the rock drill. Then, by moving the rock drill to the tip side of the guide, the rock bolt is driven into the driving hole from the tunnel cavity. And when driving the rock bolt, a washer (face plate 10) for supporting the wall surface of the tunnel cavity is attached to the rock bolt (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the method for constructing a rock bolt disclosed in Patent Document 1, although support means 8 and 9 are provided, when driving the rock bolt, the support means 8 is positioned away from the wall surface (rock face 6). Therefore, in Patent Document 1, a through hole for allowing a chuck means 12 having a diameter larger than the diameter of the rock bolt to pass through must be provided in the support means 8. Therefore, because the diameter of the through-hole provided in the support means 8 is larger than the diameter of the lock bolt, even if the lock bolt is passed through the through-hole provided in the support means 8, the lock bolt is prone to axial misalignment. Consequently, it becomes difficult to align the axis of the rock bolt with the diameter center of the hole for installation. If the rock bolt installation work is performed when the axis of the rock bolt and the diameter center of the hole for installation do not align, there is a problem in that the installation work cannot be performed smoothly and accurately. In particular, when installing steel pipe expansion type friction rock bolts (pressurized fluid expansion type rock bolts) into mounting holes, it is necessary to install the rock bolts smoothly and accurately so as not to deform them. However, if the rock bolts are installed without the axis of the rock bolts and the diameter center of the mounting holes being aligned, the steel pipe expansion type friction rock bolts may deform, and if they deform, the steel pipe expansion type friction rock bolts may not expand properly. Furthermore, in Patent Document 1, the lock bolt is attached to the lock bolt by passing it through the central through-hole of the washer, so that the washer can move on the circumferential surface of the lock bolt. Therefore, there was a risk that the washer would fall off the tip of the lock bolt when the boom was moved. In view of the above-mentioned problems, the present invention provides a method for installing rock bolts that allows for smooth and accurate installation of rock bolts and prevents accidental dropping of washers. [Means for solving the problem]

[0005] The rock bolt installation method according to the present invention involves first forming a hole for driving a rock bolt into the ground from a tunnel cavity, then providing a pressing means on a guide provided on the tip side of the boom of a construction machine so as to be movable along the extension direction of the guide, attaching the rear end of the rock bolt to the tip side of the pressing means, and then moving the pressing means toward the tip side of the guide to drive the rock bolt into the hole for driving from a tunnel cavity. ,seatA washer holding means installation step is to install a washer holding means for holding a gold on the tip side of the guide; a washer holding step is to hold a washer in the washer holding means; and a lock bolt positioning step is to move a pressing means to the tip side of the guide so that the tip of the lock bolt passes through the central through hole of the washer held by the washer holding means. After positioning the tip of the rock bolt at the entrance of the hole for installation, The boom is driven to bring the washer, held by the washer holding mechanism, closer to the wall surface around the hole for driving. ,after that, A rock bolt installation step involves moving the pressing means toward the tip of the guide to install the rock bolt into the hole for installation, and after the rock bolt has been installed, By moving the washer holding mechanism away from the hole for installation, By detaching the washer from the washer holding mechanism and leaving the washer in place at the rear end of the lock bolt, It is attached to the rear end of the lock bolt, and, It is characterized by having a washer installation step for installing washers so as to support the wall surface of the tunnel cavity. Furthermore, the means for holding the washer in the washer holding means is characterized by a magnet provided on the washer holding means. Furthermore, the washer holding means comprises a washer holding frame, the washer holding frame comprises a frame plate portion and a rear plate portion, and is configured such that a washer is detachably held in a recess formed by the inner surface of the frame plate portion and the front plate surface of the rear plate portion, and the magnet is provided on the front plate surface of the rear plate portion which is the bottom surface of the recess. Furthermore, the washer is formed from a square plate with a through hole in the center, the frame plate is formed from a frame-shaped plate in which the central part of the upper frame of a square frame is missing and open, the inner diameter of the frame plate is formed to be slightly larger than the outer diameter of the square plate forming the washer, the rear plate is formed from a plate that extends inward from the rear edge of the frame plate and has a circular central through hole with an upper opening in the center, and the magnet is provided at a position near the four corners of the square on the front surface of the rear plate which is the bottom surface of the recess. Furthermore, the lock bolt is a steel pipe expansion type friction lock bolt, and in the washer installation step, the boom is driven to move the washer holding means away from the hole for driving, so that the plate surface around the central through hole of the washer, which is away from the magnet of the washer holding means, engages with the stepped portion provided on the rear end of the steel pipe expansion type friction lock bolt driven into the hole for driving, and the washer remains on the rear end of the lock bolt, thereby installing the washer to support the wall surface of the tunnel cavity. Furthermore, the rock bolt is a type of rock bolt that is fixed to the hole wall via an anchoring material. Before driving in the rock bolt, a nut is pre-screwed onto the threaded portion formed on the rear end of the rock bolt. In the washer installation step, the boom is driven to move the washer holding means away from the hole for driving in, so that the plate surface around the central through-hole of the washer, which is away from the magnet of the washer holding means, engages with the nut, and the washer remains on the rear end of the rock bolt. After that, the nut is tightened to press the washer against the ground, thereby installing the washer to support the wall surface of the tunnel cavity. The rock bolt installation method according to the present invention provides a rock bolt installation method that allows for smooth and accurate rock bolt installation and prevents accidental dropping of washers. [Brief explanation of the drawing]

[0006] [Figure 1] A process diagram showing the installation procedure for rock bolts. [Figure 2] This is an explanatory diagram of a rock bolt, where (a) is a side view of the rock bolt, (b) is a cross-sectional view of AA in (a), and (c) is a diagram showing the expansion change of the steel pipe section of the rock bolt. [Figure 3] This diagram shows a force transmission device, with (a) being a plan view of the force transmission device and (b) being a side view of the force transmission device. [Figure 4] A side view showing the front connecting mechanism. [Figure 5] A cross-sectional view showing the sliding mechanism. [Figure 6] An exploded view showing the intermediate transmission shaft and swivel separated. [Figure 7] A front view of the washer holding mechanism, seen from the front. [Figure 8] A perspective view showing a washer detachably attached to a washer retaining mechanism. [Figure 9] A perspective view showing the washer holding mechanism and washer separately. [Modes for carrying out the invention]

[0007] Embodiment 1 As shown in Figure 1, the rock bolt installation method according to Embodiment 1 is a rock bolt installation method that involves first forming a hole H for driving a rock bolt 2 into the ground M from the tunnel cavity T, then providing a rock drill (drifter) 3 as a pressing means so as to be movable along the extension direction of the guide 34 on the tip side of the boom 32 of a face drilling machine (not shown), such as a drill jumbo (registered trademark), and attaching the rear end of the rock bolt 2 to the tip side of the rock drill 3, and then moving the rock drill 3 toward the tip side of the guide 34 to drive the rock bolt 2 into the hole H from the tunnel cavity T, and comprises the following steps (1) to (5). (1) A washer retaining means installation step, in which a washer retaining means 8 for holding a washer 9 attached to the rear end of the lock bolt 2 is installed on the tip side of the guide 34. (2) A washer holding step in which the washer 9 is held by the washer holding means 8. (3) A rock bolt positioning step in which the tip of the rock bolt 2 is passed through the central through hole 90 of the washer 9 held by the washer holding means 8 by moving the rock drill 3 toward the tip of the guide 34 (see Figure 1(b) above). (4) A rock bolt driving step in which the boom 32 is driven to bring the washer 9 held by the washer holding means 8 close to the wall surface W surrounding the hole H for driving, and the rock drill 3 is moved toward the tip of the guide 34, thereby driving the rock bolt 2 into the hole H (see Figures 1(c) and (d)). (5) After the rock bolt 2 is driven in, the washer 9 is detached from the washer holding means 8 and left on the rear end of the rock bolt 2, thereby setting the washer 9 to support the wall surface W of the tunnel cavity T (see Figure 1(e)).

[0008] Furthermore, in the rock bolt installation method according to Embodiment 1, as shown in Figure 1, the rock bolt 2 is driven using a force transmission device 1 which is provided between the rock drill 3 and the rock bolt 2 to transmit force from the rock drill 3 to the rock bolt 2. The face drilling machine is provided with, for example, a plurality of booms. A drilling device 4 is provided on the tip side of at least one boom 31, and a rock bolt mounting device 5 is provided on the tip side of at least one boom 32. Note that a boom refers to a rod-shaped structure having functions such as rising and falling, extending and contracting, and turning by an actuator such as a hydraulic cylinder. Guide cells 33 are provided on the tip sides of the booms 31 and 32. For example, the guide cell 33 has a guide 34 and a carriage 35 slidable along the guide 34. The rock drill 3 is fixed on the carriage 35, and the carriage 35 and the rock drill 3 are configured to be reciprocally movable on the guide 34 by driving a carriage drive mechanism (not shown).

[0009] As shown in Fig. 1(a), the drilling device 4 includes a rock drill 3 and a drilling rod 36 connected to the tip side of the shank rod 30 of the rock drill 3. As shown in Fig. 1(b), the rock bolt mounting device 5 includes a rock drill 3, a force transmission device 1 connected to the tip side of the shank rod 30 of the rock drill 3, and a washer holding means 8.

[0010] The booms 31 and 32 are devices that move the drilling device 4 and the rock bolt mounting device 5 to a desired position and maintain them in a desired posture. That is, after driving the boom 31 to move the drilling device 4 to a desired position and maintain it in a desired posture, the rock drill 3 is moved toward the wall surface W of the tunnel cavity T, and the rock bit 37 provided on the tip side of the drilling rod 36 is moved to the drilling position. Then, as shown in Fig. 1(a), while driving the carriage drive mechanism, the rock drill 3 is driven to press the drilling rod 36 while applying a rotational force and an impact force to the drilling rod 36, thereby drilling a hole H for inserting the rock bolt 2 from the wall surface W into the ground mass M.

[0011] Furthermore, after attaching the rock bolt 2 to the tip of the force transmission device 1 connected to the tip of the shank rod 30 of the rock drill 3, the boom 32 is driven to move the rock bolt mounting device 5 to the desired position and maintain it in the desired posture (see Figure 1(b)). Then, the rock drill 3 is moved forward in the direction approaching the hole H to insert the rock bolt 2 into the hole H (see Figures 1(c), (d), (e)). When inserting the rock bolt 2 into the hole H, it is preferable not to apply rotational or impact force to the rock bolt 2. However, if there is significant resistance when inserting the rock bolt 2 into the hole H, the rock drill 3 may, if necessary, apply impact or rotation to the rock bolt 2 while inserting it into the hole H.

[0012] As shown in Figure 2, the rock bolt 2 is, for example, a steel pipe expansion type friction rock bolt. As shown in Figure 2(a), the lock bolt 2 is configured to include a steel pipe section 20, a front end sealing section 21 that seals the front end of the steel pipe section 20, and a rear end sealing section 22 that seals the rear end of the steel pipe section 20.

[0013] The steel pipe section 20 is, for example, provided with a plating layer of molten zinc, aluminum, and magnesium on its surface, and is formed in a cross-sectional shape as shown in Figure 2(b). In other words, the steel pipe section 20, in its initial state before expansion deformation, is composed of a deformed steel pipe, as shown in Figures 2(b) and (c), which is formed by deforming the flattened cross-section of a steel pipe material with a cross-section perpendicular to the extension direction of the pipe so that both ends of the flattened cross-section (both ends in the radial direction of the pipe) are brought closer to each other, so that the outer cross-sectional shape becomes close to a circular shape. It is configured to expand and deform into a circular steel pipe shape by applying water pressure inside the deformed steel pipe.

[0014] The tip-side sealing portion 21 comprises a tip-side sealing sleeve 23 that covers the outer circumference of the tip side of the steel pipe portion 20 and seals the tip opening of the steel pipe portion 20, and a conical tip cone 24 provided at the tip of the tip-side sealing sleeve 23. The tip cone 24 is provided either integrally with the tip-side sealing sleeve 23 or separately. The tip-side sealing portion 21 may also be configured without the tip cone 24.

[0015] The rear end sealing portion 22 comprises a small-diameter sleeve 25 that covers the outer circumference of the rear end of the steel pipe portion 20, and a water injection sleeve 26 that covers the outer circumference of the rear end of the steel pipe portion 20 and seals the rear end opening of the steel pipe portion 20. The water injection sleeve 26 is located further rear than the small-diameter sleeve 25 and has a larger outer diameter than the small-diameter sleeve 25. An annular groove 27 is formed on the outer circumferential surface on the central side in the direction along the centerline of the sleeve, and is formed in an annular shape that encircles the outer circumferential surface. A water injection hole 28 is provided that penetrates from the bottom of the annular groove 27 to the inner surface of the water injection sleeve 26, and also penetrates from the outer surface to the inner surface of the steel pipe portion 20 located inside the water injection sleeve 26.

[0016] Specifically, the steel pipe section 20 is configured to expand from an irregularly shaped steel pipe to a circular steel pipe shape, as shown in Figure 2(c), due to the pressure of water injected into the inside of the steel pipe section 20 through the water injection head 50, annular groove 27, and water injection hole 28, which will be described later. Furthermore, the tip-side sealing portion 21 and the rear-side sealing portion 22 are formed from a material (for example, synthetic resin) that does not deform under the water pressure that deforms the steel pipe portion 20 from an irregularly shaped steel pipe to a circular steel pipe.

[0017] As shown in Figure 3, the force transmission device 1 comprises a rear transmission shaft 11, an intermediate transmission shaft 12, a front transmission shaft 13, a rear connecting means 15 that connects the front end of the rear transmission shaft 11 and the rear end of the intermediate transmission shaft 12, a front connecting means 16 that connects the front end of the intermediate transmission shaft 12 and the rear end of the front transmission shaft 13, and a swivel 40.

[0018] The rear connecting means 15 and the front connecting means 16 are each equipped with a sliding mechanism 6 and a limiting mechanism 7.

[0019] As shown in Figures 4 and 5, the sliding mechanism 6 consists of a spherical surface 63 formed at one end of one of the transmission shafts 61, which is arranged front to back, and a spherical seat 64, which is a recess formed at one end of the other transmission shaft 62, which is arranged front to back, and which contacts the spherical surface 63. The mechanism is configured so that the spherical surface 63 and the spherical seat 64 come into contact and slide against each other. In other words, the sliding mechanism 6 is composed of a spherical sliding mechanism in which a spherical surface 63 provided at one end of one transmission shaft 61 slides against a spherical seat 64 provided at one end of the other transmission shaft 62. In addition, Figures 4 and 5 illustrate the case where one transmission shaft 61 is the front transmission shaft 13 and the other transmission shaft 62 is the intermediate transmission shaft 12, i.e., the front connecting means 16 is shown.

[0020] The spherical surface 63 is composed of a hemispherical spherical surface formed to protrude from the plate surface (rear plate surface) 65a of a plate portion 65 provided at one end of one transmission shaft 61 (for example, the rear end of the front transmission shaft 13). The spherical seat 64 is formed by a hemispherical concave surface that is recessed from the plate surface (front plate surface) 66a of the plate portion 66 provided at one end of the other transmission shaft 62 (for example, the front end of the intermediate transmission shaft 12) and makes full contact with the spherical surface 63. The plate portions 65 and 66 are composed of, for example, circular plate portions having a circular surface.

[0021] Specifically, the plate surface 65a of the plate portion 65 is located on a plane perpendicular to the center line 61C of one of the transmission shafts 61, and the spherical surface 63 is composed of a hemispherical sphere formed to protrude from the plate surface 65a, with the center of the spherical surface 63 located on the center line 61C of one of the transmission shafts 61. Furthermore, the plate surface 66a of the plate portion 66 is located on a plane perpendicular to the center line 62C of the other transmission shaft 62, and the spherical seat 64 is composed of a hemispherical concave surface formed to be recessed from the plate surface 66a, and the center of the spherical seat 64 is located on the center line 62C of the other transmission shaft 62.

[0022] The limiting mechanism 7 is configured as follows: First, as shown in Figure 5, the center line 61C of one transmission shaft 61 and the center line 62C of the other transmission shaft 62 are aligned, and the spherical surface 63 and the spherical seat 64 are in contact. In this configuration, the plate surface 65a of the plate portion 65 of one transmission shaft 61 and the plate surface 66a of the plate portion 66 of the other transmission shaft 62 are arranged to face each other parallel to one another with a predetermined distance S between them.

[0023] Furthermore, on the peripheral edge of the plate surface 65a of one plate portion 65, four bolt holes (not shown) are formed that penetrate the plate portion 65 at 90° intervals from each other in the circumferential direction centered on the center line 61C of one transmission shaft 61. Similarly, bolt holes (not shown) are also formed in the other plate portion 66. Then, for example, the shaft of the bolt 70 is passed through the bolt hole in one plate portion 65 and the bolt hole in the other plate portion 66, the shaft of the bolt 70 is passed through the hollow part of the compression coil spring 72, and then the nut 73 is fastened from the tip side of the shaft of the bolt 70, thereby configuring the compression coil spring 72 to be mounted between the other plate portion 66 and the nut 73.

[0024] Because the limiting mechanism 7 is provided, as shown in Figure 4, when the intersection angle α between the center line 61C of one transmission shaft 61 and the center line 62C of the other transmission shaft 62 reaches a predetermined angle, the peripheral edge 65b of the plate surface (rear plate surface) 65a of one plate portion 65 and the plate surface (front plate surface) 66a of the other plate portion 66 come into contact, thereby limiting the intersection angle α so that it does not become larger than the predetermined angle. In other words, the sliding mechanism 6 is provided with a limiting mechanism 7 that limits the sliding range of the sliding mechanism 6 so that the intersection angle α between the center line 61C of one transmission shaft 61 and the center line 62C of the other transmission shaft 62 does not exceed a predetermined angle. Furthermore, the limiting mechanism 7 is configured such that the intersection angle α does not exceed, for example, a predetermined angle of 5°.

[0025] In other words, the limiting mechanism 7 is configured such that, when the spherical surface 63 and the spherical seat 64 are in contact, the plate surface (rear plate surface) 65a of the plate portion 65 of one transmission shaft 61 and the plate surface (front plate surface) 66a of the plate portion 66 of the other transmission shaft 62 are parallel to each other with a predetermined distance S between them (see Figure 5), and when the intersection angle α between the center line 61C of one transmission shaft 61 and the center line 62C of the other transmission shaft 62 becomes a predetermined angle, the peripheral edge 65b of the plate surface 65a of one plate portion 65 and the plate surface 66a of the other plate portion 66 come into contact, limiting the intersection angle α so that it does not become larger than the predetermined angle.

[0026] Although a detailed illustration of the rear connecting means 15 is omitted, the rear connecting means 15 is configured in the same way as the front connecting means 16 described above. Furthermore, since the rear connecting means 15 and the front connecting means 16 are equipped with compression coil springs 72, they have a configuration that provides excellent recovery performance from a bent state where the center line 61C of one transmission shaft 61 and the center line 62C of the other transmission shaft 62 intersect.

[0027] As shown in Figure 3, a water injection head 50 is provided at the front end of the front transmission shaft 13, to which the rear end of a steel pipe expansion type friction lock bolt 2 is attached. Furthermore, the rear end of the rear transmission shaft 11 is provided with a connecting portion 18, such as a threaded portion, for connecting to the tip of the shank rod 30 of the rock drill 3. In other words, the portion of the water injection sleeve 26, which is the rear end of the rock bolt 2, is installed and connected inside the water injection head 50, the rear end of the front transmission shaft 13 and the front end of the intermediate transmission shaft 12 are connected by a front connecting means 16 having a sliding mechanism 6 and a limiting mechanism 7, the rear end of the intermediate transmission shaft 12 and the front end of the rear transmission shaft 11 are connected by a rear connecting means 15 having a sliding mechanism 6 and a limiting mechanism 7, and a connecting portion 18 such as a threaded portion formed on the rear end of the rear transmission shaft 11 and a connecting portion such as a threaded portion formed on the tip of the shank rod 30 of the rock drill 3 (not shown) are connected via a connecting means (not shown), thereby enabling the force (pressing force, rotational force, etc.) from the rock drill 3 to be transmitted to the rock bolt 2 via the force transmission device 1. Therefore, with the force transmission device 1 described above, since it is equipped with a sliding mechanism 6, the force from the rock drill 3 is more easily transmitted to the rock bolt 2, and the work efficiency of inserting the rock bolt 2 into the hole H can be improved. Furthermore, according to the force transmission device 1 described above, even if the limiting mechanism 7 is functioning and the plate portion 65 of one transmission shaft 61 and the plate portion 66 of the other transmission shaft 62 come into contact, the force from the rock drill 3 is still transmitted to the rock bolt 2. Therefore, even if the center line of the shank rod 30 of the rock drill 3 and the center line of the rock bolt 2 are not located on the same straight line, the force from the rock drill 3 is more easily transmitted to the rock bolt 2, improving the work efficiency of inserting the rock bolt 2 into the hole H.

[0028] As shown in Figure 6, the swivel 40 is a cylindrical member that is mounted on the intermediate transmission shaft 12 so as not to rotate even when the shafts of the power transmission device 1 (rear transmission shaft 11, intermediate transmission shaft 12, front transmission shaft 13) rotate, and supplies water supplied via the intake 41 to a water channel formed on the shaft of the power transmission device 1. The water supplied to the swivel 40 via a water supply hose 39 connected to a water supply means such as a pump (not shown) and a water intake 41 formed on the intermediate transmission shaft 12 is supplied to the water inlet 50 via a water channel (not shown) formed inside the swivel 40, an annular groove 42 formed to encircle the outer surface of the intermediate transmission shaft 12, a water inlet 43 formed at the bottom of the annular groove 42, a water channel (not shown) provided inside the intermediate transmission shaft 12 that communicates with the water inlet 43, and a water channel pipe 45 connecting the water outlet 44 of the water channel to the water inlet 46 of the water inlet 50. As shown in Figure 6, the intermediate transmission shaft 12 is configured to be separable into, for example, a swivel mounting shaft 12A having a through shaft portion 12s at its rear end that penetrates the inside of the swivel 40 cylinder, and a connecting shaft 12B to which the swivel mounting shaft 12A is detachably connected. For example, the swivel mounting shaft 12A and the connecting shaft 12B are detachably connected by screw coupling between a male threaded portion 12a provided at the rear end of the swivel mounting shaft 12A and a female threaded portion 12b provided at the front end of the connecting shaft 12B. In other words, the swivel 40 is mounted so as not to rotate together with the through shaft portion 12s around the axis of the through shaft portion 12s, which is located between the flange portion 12x provided on the swivel mounting shaft 12A and the flange portion 12y provided on the front end of the connecting shaft 12B. In other words, the force transmission device 1 according to Embodiment 1 is configured to include a swivel 40 that is attached to the through shaft portion 12s so as not to rotate together with the through shaft portion 12s which serves as the transmission shaft, and which supplies water taken in from the water intake 41 to the water injection head 50 via a water channel provided on the transmission shaft (intermediate transmission shaft 12, front transmission shaft 13).

[0029] The water injection head 50 is composed of a cylindrical body with an open front end for inserting the water injection sleeve 26 of the lock bolt 2. An annular groove (not shown) corresponding to the annular groove 27 formed in the rear end sealing portion 22 of the lock bolt 2 is formed on the inner circumferential surface of the cylindrical body of the water injection head 50, and watertight maintenance members such as annular packing (not shown) are provided at positions before and after the annular groove to maintain watertightness with the outer circumferential surface of the water injection sleeve 26. Furthermore, the inner rear end of the cylindrical body of the water injection head 50 is provided with a stopper (not shown) that contacts the rear end surface 26e (see Figure 2(a)) of the water injection sleeve 26 of the lock bolt 2. When the water injection sleeve 26 of the lock bolt 2 is inserted into the water injection head 50 and the rear end surface 26e of the water injection sleeve 26 is in contact with the stopper inside the water injection head 50, as shown in Figure 3, the front end of the water injection sleeve 26 protrudes slightly forward of the front end surface 51 of the water injection head 50.

[0030] Therefore, water from a water supply means such as a water pump (not shown) is supplied into the steel pipe section 20 of the lock bolt 2 via the water supply hose 39, swivel 40, intermediate transmission shaft 12 (swivel mounting shaft 12A), water channel 45, water injection head 50, annular groove 27 of the lock bolt 2, and water injection port 28. As a result, the steel pipe section 20 expands and deforms from an irregularly shaped steel pipe to a circular steel pipe shape due to the water pressure and becomes fixed to the inner wall of the hole H.

[0031] In addition, in the case of a steel pipe expansion type friction rock bolt 2, a washer 9 is provided at the rear end of the rock bolt 2, which is inserted into the hole H and fixed in place, to support the wall surface W of the tunnel cavity T.

[0032] In Embodiment 1, as shown in Figure 1(b), a washer holding means 8 is provided on the tip side of the guide 34, and the washer 9 described above is detachably held in the washer holding means 8. As shown in Figures 7 to 9, the washer holding means 8 is configured to include a washer holding frame 80 and a mounting portion 81 for the guide 34.

[0033] The washer retaining frame 80 comprises a frame plate portion 82 and a rear plate portion 83. The frame plate portion 82 is formed, for example, by a frame-shaped plate in which the central part of the upper frame portion of a rectangular frame body, whose centerline extends in the front-rear direction, is missing and has an opening. The rear plate portion 83 is formed from a plate that extends from the rear end edge of the frame plate portion 82 into the inside of the frame of the frame plate portion 82, and has a circular central through-hole 84 with an upper opening formed in the center. The inner surface of the frame plate portion 82 and the front surface of the rear plate portion 83 are formed on mutually perpendicular surfaces. The washer 9 is then detachably held within a recess 85 formed by the inner surface of the frame plate portion 82 and the front surface of the rear plate portion 83. For example, magnets 86 are attached to the front surface of the rear plate portion 83, which forms the bottom surface of the recess 85, near the four corners, to serve as a means for the washer holding means 8 to hold the washer 9. The inner diameter of the frame plate portion 82 is formed to be slightly larger than the outer diameter of the rectangular plate that forms the washer 9. Then, with the rear plate surface 91 of the washer 9 facing the front plate surface of the rear plate portion 83 that forms the bottom surface of the recess 85, the washer 9 is placed in the recess 85, and the rear plate surface 91 of the washer 9 is attracted to the magnets 86, 86..., thereby holding the washer 9 detachably within the recess 85. Furthermore, the washer holding means 8 is fixed to the guide 34 by fixing the mounting portion 81 to the guide 34 with a fixing means 87 such as a bolt.

[0034] Therefore, with the lock bolt 2 passed through the central through-hole 90 of the washer 9 held in the recess 85 of the washer holding means 8 (see Figure 1(b)), when the lock bolt 2 is moved to the installation position on the wall surface W and then inserted into the hole H, the washer 9 held by the washer holding means 8 functions as a means to prevent misalignment of the lock bolt 2 (centralizer), making it easier to insert the lock bolt 2 into the hole H.

[0035] Next, we will explain the rock bolt installation method. First, as shown in Figure 1(a), a drilling device 4 attached to the boom 31 is used to drill holes H in the wall surface W of the tunnel cavity T at predetermined positions for inserting the rock bolts 2. Next, the rock bolt mounting device 5 is constructed by attaching the force transmission device 1 to the rock drill 3 mounted on the boom 32 and attaching the washer holding means 8 to the tip side of the guide 34 (washer holding means installation step), and the rock bolt 2 is attached to the water injection head 50 on the front end side of the force transmission device 1 in the rock bolt mounting device 5. The washer 9 is also set to be held in the recess 85 of the washer holding means 8 (washer holding step). Then, by operating the carriage 35 to move the rock drill 3, the rock bolt 2 is passed through the central through hole 90 of the washer 9 from the tip side, as shown in Figure 1(b) (rock bolt positioning step). Next, the boom 32 and carriage 35 are operated to move the rock bolt 2 toward the hole H, positioning the tip of the rock bolt 2 at the entrance of the hole H. Then, the boom 32 is operated to bring the front plate surface 92 of the washer 9, held by the washer holding means 8, closer to the wall surface W. Then, the carriage 35 is operated to move the rock drill 3 forward while advancing the rock bolt 2, thereby inserting the rock bolt 2 into the hole H (rock bolt installation step) (see Figures 1(c) and (d)). That is, as shown in Figure 1(d), when the front plate surface 92 of the washer 9 and the wall surface W come into contact and it becomes impossible to move the rock drill 3 forward, the insertion of the rock bolt 2 into the hole H is complete.

[0036] Once the insertion of the rock bolt 2 into the hole H is complete, water is injected into the steel pipe section 20 of the rock bolt 2. For example, when the water pressure inside the steel pipe section 20 of the rock bolt 2 reaches a predetermined construction water pressure, the injection pump (not shown), which serves as the water supply means, is stopped, thereby completing the water injection into the steel pipe section 20 of the rock bolt 2. When the water injection process is complete, the steel pipe section 20 between the front sealing section 21 and the rear sealing section 22 expands and deforms from the state shown by the solid line in Figure 2(a) to the state shown by the dashed line, and the outer surface of the expanded steel pipe section 20 between the front sealing section 21 and the rear sealing section 22 becomes fixed to the hole wall W inside the hole H.

[0037] Furthermore, the diameter of the central through-hole 90 of the washer 9 is formed to correspond to the outer diameter of the small-diameter sleeve 25 of the lock bolt 2. Therefore, when the insertion of the lock bolt 2 into the hole H is complete, the inner circumferential surface of the central through hole 90 of the washer 9 and the outer circumferential surface of the small diameter sleeve 25 are in close proximity, the washer 9 is positioned on the circumferential surface of the small diameter sleeve 25, and the rear plate surface 91 of the washer 9 and the front end surface 29 of the water injection sleeve 26 (the stepped surface that forms the boundary between the outer circumferential surface of the small diameter sleeve 25 and the outer circumferential surface of the water injection sleeve 26 (see Figure 2(a))) are in close proximity. Subsequently, as shown in Figure 1(e), the boom 32 is operated to move the lock bolt mounting device 5 away from the hole H. As a result, the water injection head 50 of the force transmission device 1 detaches from the water injection sleeve 26. Furthermore, as the washer holding means 8 moves away from the hole H, the washer 9 detaches from the magnets 86, 86... of the washer holding means 8, and the washer 9 catches (engages) with the front end surface 29 of the water injection sleeve 26, so that the washer 9 for supporting the wall surface W of the tunnel cavity T is attached to the rear end of the lock bolt 2 (washer installation step).

[0038] According to Embodiment 1, the force transmission device 1, which is provided between the rock drill 3 and the rock bolt 2 to transmit force from the rock drill 3 to the rock bolt 2, is equipped with a rear connecting means 15 having a sliding mechanism 6 and a limiting mechanism 7, and a front connecting means 16, so that excessive force is not applied to the rock bolt 2 and the rock bolt can be inserted straight into the hole H. In particular, in the case of steel pipe expansion type friction type rock bolt 2, if the steel pipe section 20 bends, it becomes impossible to reliably inject water into the steel pipe section 20, and it may become impossible to fix the rock bolt 2 to the hole wall of the hole H. Therefore, being able to insert the steel pipe expansion type friction type rock bolt 2 straight into the hole H has the excellent effect of enabling accurate and reliable installation of the steel pipe expansion type friction type rock bolt 2.

[0039] Furthermore, since the rear connecting means 15 and the front connecting means 16 are equipped with a sliding mechanism 6 and a limiting mechanism 7, even if the center line of the shank rod 30 of the rock drill 3 and the center line of the rock bolt 2 are not aligned on the same straight line, the force from the rock drill 3 is more easily transmitted to the rock bolt 2, making it possible to efficiently insert the rock bolt straight into the hole H.

[0040] Furthermore, since the force transmission device 1 includes a rear transmission shaft 11, an intermediate transmission shaft 12, a front transmission shaft 13, a rear connecting means 15 that connects the front end of the rear transmission shaft 11 to the rear end of the intermediate transmission shaft 12, and a front connecting means 16 that connects the front end of the intermediate transmission shaft 12 to the rear end of the front transmission shaft 13, the degree of freedom in the bending direction of the axes of the rear transmission shaft 11, intermediate transmission shaft 12, and front transmission shaft 13 is increased, and excessive force is more effectively prevented from being applied to the lock bolt 2.

[0041] Furthermore, since the power transmission device 1 is equipped with a swivel 40, when the shafts of the power transmission device 1 (rear transmission shaft 11, intermediate transmission shaft 12, front transmission shaft 13) are rotated, it is possible to prevent the water supply hose 39 connected to the water intake port 41 of the swivel 40 from becoming entangled with the shafts. In other words, even when the shafts of the power transmission device 1 are rotated, the water supply hose 39 connected to the water intake port 41 will not become entangled with the shafts.

[0042] Furthermore, the rock bolt mounting device 5 is configured to include a rock drill 3, a force transmission device 1 according to Embodiment 1 connected to the tip side of the shank rod 30 of the rock drill 3, and a washer holding means 8. By passing the rock bolt 2 through the central through hole 90 of the washer 9 held in the recess 85 of the washer holding means 8, the washer 9 held by the washer holding means 8 can function as a means to prevent the rock bolt 2 from shifting, making it easier to insert the rock bolt 2 into the hole H. In other words, according to the installation method of the lock bolt according to the embodiment, a washer 9 having a central through hole 90 formed to be approximately the same diameter as the lock bolt 2, that is, a central through hole 90 formed to be slightly larger in diameter than the lock bolt 2, can be used, and by passing the tip side of the lock bolt 2 through the central through hole 90 of the washer 9 held by the washer holding means 8, the lock bolt 2 becomes less likely to shift axially. Therefore, it becomes easier to align the axis of the rock bolt 2 with the diameter center of the hole H for installation, allowing the installation work to be carried out smoothly and accurately. In particular, it becomes possible to smoothly and accurately drive the steel pipe expansion type friction rock bolt 2 into the installation hole H without deformation, and to properly expand the steel pipe expansion type friction rock bolt 2, thereby enabling the installation work of the steel pipe expansion type friction rock bolt 2 to be carried out smoothly and accurately. On the other hand, since the aforementioned Patent Document 1 does not have a configuration corresponding to the washer holding means 8, it is more difficult to drive the rock bolts smoothly and accurately compared to the rock bolt installation method according to the embodiment.

[0043] Furthermore, according to the rock bolt installation method of the embodiment, when moving the boom 32 to position the rock bolt 2 for installation, the washer 9 is held by the washer holding means 8, thereby preventing the washer 9 from unexpectedly falling. On the other hand, the aforementioned Patent Document 1 does not have a configuration corresponding to the washer holding means 8 of the present invention. Instead, the lock bolt is passed through the central through-hole of the washer, and the washer is attached to the lock bolt so that it can move on the circumferential surface of the lock bolt. Consequently, there was a risk that the washer would fall off the tip of the lock bolt when the boom was moved.

[0044] Furthermore, according to the rock bolt installation method of the embodiment, a washer holding means 8 for holding a washer 9 attached to the rear end of the rock bolt 2 is installed on the tip side of the guide 34, and the boom 32 is driven so that the washer 9 held by the washer holding means 8 can be brought close to the wall surface W around the hole H for driving, and after the rock bolt 2 is driven, the boom 32 is driven to move the washer holding means 8 away from the wall surface W, thereby detaching the washer 9 from the washer holding means 8. Therefore, if a washer 9 made of the aforementioned rectangular plate is used as the washer 9, the washer 9 will be attached to the rear end of the rock bolt 2 in the same position it was in when it was held by the washer holding means 8 after the rock bolt 2 is driven in. As a result, the edges of each washer 9,9... attached to each rock bolt 2,2... will be unified so that they extend horizontally and vertically. In other words, each washer 9,9... made of a rectangular plate can be attached to the rear end of each rock bolt 2,2... so that its edges are aligned horizontally and vertically, making it possible to construct a wall surface where the edges of each washer 9,9... installed on the wall surface W after the rock bolts have been driven in are neatly aligned horizontally and vertically. On the other hand, Patent Document 1 does not have a configuration equivalent to the washer holding means 8. Therefore, when a washer made of a square-shaped plate is used, the washer is more likely to rotate around the axis of the lock bolt as the center of rotation. As a result, there is a high possibility that the edges of each washer installed on the wall surface after the lock bolt has been driven in will not be aligned horizontally or vertically.

[0045] In other words, according to the rock bolt installation method of the embodiment, the rock bolt 2 can be driven in smoothly and accurately, the washer 9 can be prevented from falling unexpectedly, and the washers 9, 9, etc. installed on the wall surface W after each rock bolt 2, 2, ... is driven in can be neatly aligned.

[0046] Embodiment 2 In Embodiment 1, a force transmission device 1 was illustrated that includes a rear transmission shaft 11, an intermediate transmission shaft 12, a front transmission shaft 13, a rear connecting means 15 that connects the front end of the rear transmission shaft 11 to the rear end of the intermediate transmission shaft 12, and a front connecting means 16 that connects the front end of the intermediate transmission shaft 12 to the rear end of the front transmission shaft 13. However, a force transmission device with only one connecting means may also be provided. In other words, when driving a rock bolt into the ground from a tunnel cavity, the force transmission device provided between the rock drill and the rock bolt to transmit force from the rock drill to the rock bolt comprises a rear transmission shaft with its rear end attached to a pressing means, a front transmission shaft with a rock bolt attached to its front end, and a connecting means that connects the front end of the rear transmission shaft and the rear end of the front transmission shaft. The connecting means may be configured to include a sliding mechanism between the front end of the rear transmission shaft and the rear end of the front transmission shaft that operates to allow the centerlines of the rear transmission shaft and the front transmission shaft to intersect, and a limiting mechanism that limits the sliding range of the sliding mechanism so that the intersection angle between the centerlines of the rear transmission shaft and the front transmission shaft does not exceed a predetermined angle. In other words, the force transmission device may have a configuration comprising a rear transmission shaft, a front transmission shaft, and a connecting means.

[0047] In the above example, a washer 9 made of a rectangular plate having a rectangular surface was given, but the washer may also be made of a circular plate having a circular surface, for example. In this case, the washer holding means may be configured to have a recess that can accommodate a washer made of a circular plate, and a magnet on the bottom surface of the recess for attracting and holding the washer.

[0048] Furthermore, while the above example illustrates a steel pipe expansion type friction lock bolt 2 that expands and deforms with water pressure, a steel pipe expansion type friction lock bolt that expands and deforms with air pressure may also be used. In other words, as a lock bolt, a steel pipe expansion type friction lock bolt that expands and deforms with fluid pressure such as water or air should be used.

[0049] Furthermore, although the above example illustrates a construction method for installing steel pipe expansion type friction rock bolts 2, the rock bolt construction method according to the present invention can also be used when installing rock bolts such as steel bars that are fixed to the hole wall of hole H via an anchoring material such as mortar or resin into hole H. In the case of a lock bolt with a fixing material, a nut can be pre-screwed onto the threaded portion formed on the rear end of the lock bolt. After the lock bolt has been secured into the hole H, the nut can be tightened further to secure the washer 9 to the wall surface W. In other words, if the rock bolt is a type of rock bolt that is fixed to the hole wall via an anchoring material, a nut should be pre-screwed onto the threaded portion formed at the rear end of the rock bolt before it is driven in. In the washer installation step, the boom 32 is driven to move the washer holding means 8 away from the hole H for driving, so that the plate surface around the central through-hole 90 of the washer 9, which is away from the magnet 86 of the washer holding means 8, catches (engages) with the nut, and the washer 9 remains at the rear end of the rock bolt. Then, the nut is tightened to press the washer 9 against the ground M, so that the washer 9 is installed to support the wall surface W of the tunnel cavity T. Even in this case, by passing the tip of the lock bolt through the central through-hole 90 of the washer 9 held by the washer holding means 8, the lock bolt is less likely to shift axially. This makes it easier to align the axis of the lock bolt with the diameter center of the hole H for driving, allowing the driving work to be performed smoothly and accurately.

[0050] Furthermore, although the above example illustrates a method for installing rock bolts using a force transmission device, the rock bolt installation method according to the present invention is also applicable in cases where a force transmission device is not used.

[0051] Furthermore, although the above example shows the use of a rock drill as the pressing means, the pressing means may be a machine other than a rock drill. In other words, in the present invention, the pressing means can be any means that applies a pressing force to the rock bolt. [Explanation of symbols]

[0052] 2 rock bolt, 3 rock drill (pressing means), 8 washer holding means, 9 washer, 32 Boom, 34 Guide, 86 Magnet, 90 Central through-hole of washer, H Hole for concrete placement, M Ground, T Tunnel cavity, W Wall.

Claims

1. A method for installing rock bolts, comprising: forming a hole for driving rock bolts into the ground from the tunnel cavity; providing a pressing means on a guide on the tip side of the boom of a construction machine so as to be movable along the extension direction of the guide; attaching the rear end of the rock bolt to the tip side of the pressing means; and then moving the pressing means toward the tip side of the guide to drive the rock bolt into the hole for driving rock bolts from the tunnel cavity, A washer retaining means installation step involves installing a washer retaining means for holding a washer on the tip side of the guide, A washer holding step that causes a washer to be held by a washer holding means, A lock bolt positioning step involves moving the pressing means toward the tip of the guide to pass the tip of the lock bolt through the central through-hole of the washer held by the washer holding means, A rock bolt driving step involves positioning the tip of the rock bolt at the entrance of the hole to be driven, driving the boom to bring the washer held by the washer holding means close to the wall surface around the hole, and then moving the pressing means toward the tip of the guide to drive the rock bolt into the hole. A method for installing a rock bolt, comprising a washer installation step, in which, after driving in the rock bolt, the washer retaining means is moved away from the hole for driving in, thereby detaching the washer from the washer retaining means and leaving the washer on the rear end of the rock bolt, thereby installing the washer so as to be attached to the rear end of the rock bolt and to support the wall surface of the tunnel cavity.

2. The method for installing a lock bolt according to claim 1, characterized in that the means for holding the washer in the washer holding means is a magnet provided in the washer holding means.

3. The washer holding means comprises a washer holding frame, The washer retaining frame comprises a frame plate portion and a rear plate portion, and is configured such that the washer is detachably held within a recess formed by the inner surface of the frame plate portion and the front plate surface of the rear plate portion. The method for installing a lock bolt according to claim 2, characterized in that the magnet is provided on the front surface of the rear plate portion which forms the bottom surface of the recess.

4. The washer is formed from a rectangular plate with a through hole in the center, The frame plate section is formed by a frame-shaped plate in which the central part of the upper frame section of a rectangular frame body is missing and opened. The inner diameter of the frame plate is formed to be slightly larger than the outer diameter of the rectangular plate that forms the washer. The rear plate portion extends from the rear edge of the frame plate portion into the inside of the frame plate portion, and is formed by a plate with a circular central through-hole with an upper opening in the center. The method for installing a lock bolt according to claim 3, characterized in that the magnet is provided near the four corners of a square on the front surface of the rear plate portion which forms the bottom surface of the recess.

5. The rock bolt is a steel pipe expansion type friction rock bolt. The method for installing a rock bolt according to claim 2, characterized in that in the washer installation step, the boom is driven to move the washer holding means away from the hole for installation, so that the plate surface around the central through-hole of the washer, away from the magnet of the washer holding means, engages with the stepped portion provided on the rear end of the steel pipe expansion type friction rock bolt installed in the hole for installation, and the washer remains on the rear end of the rock bolt, thereby installing the washer to support the wall surface of the tunnel cavity.

6. A rock bolt is a type of rock bolt that is fixed to the hole wall via an anchoring material. Before installing the rock bolt, pre-screw a nut onto the threaded portion formed at the rear end of the rock bolt. The method for installing a rock bolt according to claim 2, characterized in that in the washer installation step, the boom is driven to move the washer holding means away from the hole for installation, so that the plate surface around the central through-hole of the washer, which is away from the magnet of the washer holding means, engages with the nut, the washer remains at the rear end of the rock bolt, and then the nut is tightened to press the washer against the ground, thereby installing the washer to support the wall surface of the tunnel cavity.

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