JP5784335B2 - Grand anchor placing apparatus and placing method - Google Patents

Description

  The present invention relates to a ground anchor placing apparatus and a placing method, and more particularly, to a ground anchor placing apparatus and a placing method that allow a ground anchor made of a wire rope to be inserted and fixed while drilling in a natural ground.

The ground anchor is used for reinforcing the front of the face in a mountain tunnel, as well as a temporary structure such as supporting a root wall, or a permanent structure such as securing a stable slope and preventing landslides. (See Patent Document 1 or 2).
On the other hand, a double-pipe drilling method is mainly used for placing this type of ground anchor on a natural ground or ground. Hereinafter, a method for placing a ground anchor used as a support for a root-cutting retaining wall will be described with reference to FIG.

  As shown in FIG. 13A, a double pipe drilling device 70 used for placing such a ground anchor includes an outer pipe 72 having an outer bid 7202 rotatably attached to the tip, and an outer pipe. 72, the inner pipe 74 inserted into the inner pipe 74, the inner bid 7402 provided at the front end of the inner pipe 74 and detachably engaged with the inner side of the outer bid 7202, and the rear end of the inner pipe 74. Rotation striking mechanism 76 for imparting rotation and striking force to 74, and push-in mechanism 78 for moving inner pipe 74 and outer pipe 72 including rotary striking mechanism 76 in the direction of excavation to natural ground 82. The double-pipe drilling device 70 configured as described above is used by being mounted on the traveling device 80 via the frame 81.

  When a ground anchor used for supporting the retaining wall 84 of the natural ground 82 is to be driven using the double pipe drilling device 70, first, the outer bid of the double pipe drilling device 70 attached to the traveling device 80 is set. The rotary impact mechanism 76 and the push-in mechanism 78 are driven in a state where the front end surfaces of 7202 and the inner bid 7402 are pressed against the outer surface of the retaining wall 84. When the rotary striking mechanism 76 and the pushing mechanism 78 are driven, the pushing force by the pushing mechanism 78 and the rotation and striking force by the rotating striking mechanism 76 are transmitted to the inner bid 7402 through the inner pipe 74, and the outer bid 7202 is also sent to the inner bid 7202 at the same time. The propeller is propelled while being rotated integrally with the bid 7402. Thereby, the earth retaining wall 84 is excavated. Then, the inner bid 7402 and the outer bid 7202 penetrating the earth retaining wall 84 pierce the natural ground 82 by the pushing force by the pushing mechanism 78 and the rotation and hitting by the rotary hitting mechanism 76, and as shown in FIG. 86 is formed. At the same time, the outer tube 72 is pushed in the direction in which the hole 86 advances by the pushing force of the pushing mechanism 78 to cover the collapse of the hole 86.

  At this time, drilled water is supplied from the water supply port 88 to the outer bid 7202 and the inner bid 7402 through the inner pipe 74. Then, the flour (slime) excavated by the outer bid 7202 and the inner bid 7402 is transferred from the well-known return passage provided in the inner bid 7402 by the perforated water supplied to the outer bid 7202 and the inner bid 7402. Is discharged to the outside through a space formed between the inner periphery of the inner tube and the outer periphery of the inner tube 74.

  If a hole 86 having a desired fixed length (for example, about 10 m to 15 m) is formed in the natural ground 82, the inner pipe 74 is rotated in the direction opposite to the excavation direction, and the inner bid 7402 is engaged with the outer bid 7202. Release the match. In this state, by operating the pushing mechanism 78 in the direction opposite to the pushing direction, the inner tube 74 including the inner bid 7402 is pulled out as shown in FIG. Thereafter, the inside of the hole 86 is cleaned by injecting cleaning water through the outer tube 72.

Next, as shown in FIG. 13 (c), a wire rope 90 made of PC steel strand or multi-PC steel strand called tendon is inserted through the outer tube 72 to the vicinity of the back end of the hole 86. . Thereafter, as shown in FIG. 13 (d), a grout 94 such as cent milk is added through the outer pipe 72 while the outer pipe 72 is pulled out by a drawing jack 9204 driven by a hydraulic unit 9202 mounted on the small transporter 92. Inject pressure.
When the pressure injection of the grout 94 is completed, the wire rope 90 is tensioned by the tension jack 89 as shown in FIG. Thereafter, as shown in FIG. 13F, the wire rope 90 is fixed by the fixing plate 96 and fixed. Thereby, a ground anchor can be driven in a natural ground.

JP-A-5-239830 Japanese Patent Laid-Open No. 9-1000068

In the conventional double-pipe drilling method for ground anchor as described above, the dust (slime) generated by excavation is formed between the inner periphery of the outer tube 72 and the outer periphery of the inner tube 74 together with the drilling water. Since the dust can be discharged out of the hole 86 through the space formed between them, the dusting can be reliably discharged out of the hole 86 and can be used for various grounds. Can be done easily with a jack.
However, the conventional ground anchor placing method requires a step of drawing the inner pipe 74 including the inner bid 7402 and then inserting the wire rope 90 into the hole 86 through the outer pipe 72. In addition to 74, an outer tube 72 is also required. For this reason, in addition to the step of inserting the wire rope 90, a step of pulling out the inner tube 74 and the outer tube 72 is required, which increases the number of steps and makes the placement of the ground anchor complicated. In addition, it takes a lot of time and has a problem that the driving efficiency is low and the cost is high.

  The present invention has been made in view of the circumstances as described above, and an object thereof is to provide a ground anchor placing apparatus and a placing method capable of reducing the number of execution steps required for placing a ground anchor. is there.

In order to achieve the above-mentioned object, the present invention is a ground anchor placing device, which is a hollow boring rod to which rotation and striking force are applied for drilling a natural ground, and the boring rod at the tip of the boring rod. A bit adapter provided so as to be incapable of moving in the axial direction of the boring rod by matching the axis of the boring rod and rotating integrally with the boring rod, and the axis of the bit adapter and the axis of the bit adapter being aligned with the tip of the bit adapter The bit adapter and the bit adapter and the bit bit, and the bit adapter and the bit adapter can be coupled with each other by operating from the base end side of the boring rod. An attachment / detachment mechanism for separating the perforated bit, and one end in the axial direction disposed on the outer periphery of the bit adapter An outer member formed on the perforated bit with an outer diameter that is connected to the perforated bit so as to be rotatable about the axis of the perforated bit and immovable in the axial direction of the perforated bit, and is inserted into a hole perforated by the perforated bit; A connecting mechanism for connecting one end of a plurality of wire ropes provided on the outer member and arranged along the length direction of the boring rod, and the outer member is arranged around the axis of the drilling bit. A casing shoe rotatably connected to the drill bit in an axial direction, and a cylindrical shoe connected to the casing shoe and extending radially outward of the boring rod toward the proximal end of the boring rod. It is characterized by including a wire connection sleeve .

The present invention also relates to a ground anchor placing method, wherein a bit adapter is provided at the tip of a hollow boring rod, a drill bit is provided at the tip of the bit adapter so as to be separable, and an axis of the drill bit at the outer periphery of the bit adapter An outer member is coupled to the perforated bit so as to be rotatable around, and one end of a plurality of wire ropes is coupled to a plurality of locations spaced in the circumferential direction of the outer member on the radially outer side of the boring rod, and the boring The rod is given rotation and striking force and pushing force, and the drill bit is drilled to a certain depth while drilling a natural ground, and at the same time, the wire rope is sequentially put into the drilled hole by the outer member. After the completion of the drilling and pulling-in step and the drilling into the natural ground, the bit adapter is separated from the drilling bit. A grout injection step of pressure-injecting grout into the hole through the boring rod while pulling out the bit adapter and the boring rod from the hole while leaving the perforated bit, the outer member, and the wire rope in the hole. The bit adapter is separated from the drilled bit by rotating the boring rod in the reverse direction to the time of drilling and then pulling out the boring rod .

  According to the ground anchor placing apparatus and the placing method of the present invention, it is possible to insert and fix a wire rope into a hole drilled while drilling in a natural ground. Thereby, the number of enforcement steps required for placing the ground anchor can be reduced, and the efficiency and cost reduction of placing can be achieved.

Sectional drawing of the principal part which shows an example of the ground anchor placement apparatus concerning this invention. FIG. 2 is a front view of a drill bit viewed from the direction of arrow A in FIG. 1. The side view of the partial notch of the wire connection sleeve which comprises the wire rope connection member in the ground anchor placement apparatus of this invention. The bottom view of the wire connection sleeve seen from the arrow B direction of FIG. Explanatory drawing which shows the operation | movement procedure of the ground anchor placement apparatus concerning this invention. Explanatory drawing which shows the example of mounting of the stabilizer to the casing shoe in the grand anchor placement apparatus of this invention. Explanatory drawing which shows the other example of the wire rope connection system in the ground anchor placement apparatus of this invention. The side view for description which shows the modification of the connection system to the wire connection sleeve of the wire rope in the grand anchor placement apparatus of this invention. Sectional drawing which follows the CC line | wire of FIG. Explanatory drawing which shows the further another example of the wire rope connection system in the ground anchor placement apparatus of this invention. The front view for description of the tunnel reinforced with the wire rope cast | placed with the grand anchor placement apparatus of this invention. The longitudinal cross-sectional side view of the tunnel which shows the state by which the wire rope nailed with the ground anchor placement apparatus of this invention was nailed in the natural ground and the face direction. Explanatory drawing which shows the work procedure of the conventional grand anchor placement method.

(First embodiment)
A first embodiment of a ground anchor placing apparatus according to the present invention will be described with reference to FIGS.
The ground anchor placing apparatus 100 shown in the first embodiment improves the ground of a soft ground layer where a tunnel is excavated, reinforces ground such as a face, or supports a temporary structure or a cutout for supporting a retaining wall. It is a type that is self-punched in the natural ground as a ground anchor for permanent structures such as ensuring stability of the slope, boring rod 12, bit adapter 14, drill bit 16, casing shoe 18, wire rope 20, connection A mechanism 22, a bit tip conduit 24, an attachment / detachment mechanism 30 and the like are included.

  The boring rod 12 transmits rotation, striking force, and digging force applied from a well-known drilling machine (rotary percussion or the like) (not shown) to the drill bit 16 so that drill water or grout can be injected. It is composed of a hollow metal rod. Further, the boring rod 12 is constituted by connecting a plurality of rods 1202 having a length of about 1 m to 5 m in a straight line by a coupling 1204. In this case, the entire length of the boring rod 12 is set by the depth of the hole drilled in the natural ground, and is, for example, about 10 m to 20 m. Therefore, in the actual drilling of the natural ground, the rod 1202 having a length of about 1 m to 5 m is sequentially added by the coupling 1204 to secure the boring rod 12 having a length necessary for the drilling of the natural ground. Yes.

  The bit adapter 14 transmits the drilling rotation and striking force applied to the boring rod 12 to the drilling bit 16. The boring rod 12 is aligned with the axis of the boring rod 12 at the tip of the boring rod 12. It is provided so that it cannot move in the axial direction and rotates integrally with the boring rod 12.

  The piercing bit 16 pierces a natural ground by rotation and striking force applied through the boring rod 12 and the bit adapter 14, and the axis of the bit adapter 14 is aligned with the axis of the bit adapter 14 to attach / detach the mechanism 30. Is detachably provided. The drill bit 16 is left in the hole drilled as a lost bit after drilling a natural ground.

  The attachment / detachment mechanism 30 is formed concentrically from the bit adapter 14 side in the axial center portion of the drill bit 16, and has a bottomed fitting hole 3002 into which the tip end portion of the bit adapter 14 is detachably inserted, and the fitting hole 1602. A plurality of locking claws 3004 projecting from the inner peripheral wall at a predetermined interval in the circumferential direction and an outer peripheral surface of the tip of the bit adapter 14 at a predetermined interval in the circumferential direction, Each locking claw 3004 has a plurality of locking recesses 3006 that are individually engaged and disengaged.

The fitting hole 3002, the locking claw 3004, and the locking recess 3006 of the attaching / detaching mechanism 30 make it impossible for the bit adapter 14 and the drilled bit 16 to move in the axial direction thereof so that they can be integrally rotated and separated. Further, the locking claw 3004 can be removed from the proximal end side of the boring rod 12 by the rotation operation, and the bit adapter 14 and the drilled bit 16 can be separated.
The perforated bit 16 has a perforated water outflow passage 1604 communicating with the hollow portion 1206 of the boring rod 12 through the axial hole 1402 of the bit adapter 14.

When combining drilling bit 16 to the tip of the bit adapter 14 by inserting the tip of the bit adapter 14 into the fitting hole 3002 of the drilling bit 16, a boring rod 12 including bit adapter 14, when even field meter around Rotate to. Thereby, since the latching claw 3004 is latched by the latching recessed part 3006, the drilling bit 16 and the bit adapter 14 are hold | maintained in the combined state which cannot be isolate | separated. Further, when the boring rod 12 including the bit adapter 14 is rotated in the direction opposite to the clockwise direction, the locking claw 3004 is detached from the locking recess 3006, and the perforated bit 16 and the bit adapter 14 are separable. .

  Note that the flour generated by the drilling of the drill bit 16 is drilled through a gap generated between the outer peripheral surface of the drill bit 16, the casing shoe 18 and the coupling mechanism 22 and the inner peripheral surface of the natural mountain formed by the drilling. It is discharged out of the hole with water. In addition, by providing the perforated bit 16 with a dust taking-in passage 1608 as shown by a broken line in FIG. It is also possible to discharge to the outside of the hole through the gap formed between the outer periphery of the wire 14 and the inside of the bit leading conduit 24.

  The casing shoe 18 transmits the rotation and striking force transmitted from the boring rod 12 through the bit adapter 14 to the drilling bit 16, and the rotation of the drilling bit 16 due to the drilling is transmitted to the casing shoe 18, the coupling mechanism 22 and the bit tip conduit 24. It is intended not to be transmitted. For this purpose, the casing shoe 18 is rotatably fitted to the outer periphery of the coupling end 1606 of the drill bit 16 with the bit adapter 14 and has a first cylindrical portion 1802 having an outer diameter smaller than the outer diameter of the drill bit 16; A second cylindrical portion 1804 having an outer diameter smaller than the outer diameter of the first cylindrical portion 1802 provided at the end opposite to the drilling bit 16 of the first cylindrical portion 1802 toward the boring rod 12 side, and a second cylinder A first cylindrical portion 1802 opposite to the first cylindrical portion 1802 and extending toward the boring rod 12, and a third cylindrical portion 1806 having an outer diameter smaller than the outer diameter of the second cylindrical portion 1802. The axes of the first to third cylindrical portions 1802 to 1804 coincide.

The thus configured casing shoe 18 is connected to the drill bit 16 so as to be rotatable about its axis. For this purpose, a male screw 1606 a is formed on the outer periphery of the coupling end 1606 of the drill bit 16, and a female screw 1802 a is formed on the inner periphery of the first cylindrical portion 1802. Then, the male screw 1606a is screwed into the female screw 1802a so that the both screws are disengaged as shown in FIG. 1, so that the casing shoe 18 and the drill bit 16 are rotatably connected, and these Are connected so that they cannot be separated from each other.
Note that the casing shoe 18 and the drill bit 16 can be separated by rotating the casing shoe 18 or the drill bit 16 in a direction opposite to the screwing direction of the male screw 1606a with the female screw 1802a.

The connecting mechanism 22 is for connecting the wire rope 20 as a tension member of the ground anchor to the casing shoe 18, and from the cylindrical wire connecting sleeve 2202 having a length extending from the casing shoe 18 to the boring rod 12 side. Become. One end of the wire connection sleeve 2202 is engaged with the outer periphery of the second cylindrical portion 1804 of the casing shoe 18 so as to be rotatable around the axis of the casing shoe 18, and the other end portion of the wire connection sleeve 2202 is provided with a plurality of wire ropes 20. A plurality of connecting holes 2204 to which one ends of the wire connecting sleeves 2202 are connected separately are formed at regular intervals along the circumferential direction of the wire connecting sleeve 2202.
As shown in FIG. 1, a metal coupling fitting 26 is fixed to one end of the wire rope 20. The wire rope 20 is coupled to the wire coupling sleeve 2202 by fitting the coupling fitting 26 into the coupling hole 2204 of the wire coupling sleeve 2202. Moreover, the wire rope 20 is comprised from a PC steel rod, PC steel strand, multiple PC steel strand, a continuous fiber reinforcement material, etc.

In order to rotatably connect the wire connecting sleeve 2202 to the outer periphery of the second cylindrical portion 1804 of the casing shoe 18, a male screw 1804 a is formed on the outer periphery of the second cylindrical portion 1804, and a female screw 2202 a is formed on the inner periphery of one end of the wire connecting sleeve 2202. Form. Then, the male screw 1804a is screwed into the female screw 2202a, and the screw connection between both is made free as shown in FIG. 1, so that the wire connecting sleeve 2202 and the casing shoe 18 are rotatably connected, and These are connected so that they cannot be separated from each other.
The casing shoe 18 and the wire connecting sleeve 2202 can be separated by rotating the casing shoe 18 or the wire connecting sleeve 2202 by rotating the male screw 1804a in the direction opposite to the screwing direction of the female screw 2202a.

As shown in FIG. 1, a plurality of stabilizers 28 that engage with the inner peripheral portion of the hole drilled by the drill bit 16 and suppress the rotation of the wire connection sleeve 2202 are provided on the outer peripheral surface of the wire connection sleeve 2202. The connecting sleeve 2202 is provided at regular intervals along the circumferential direction. The stabilizer 28 bites into the inner wall of the drilled hole, thereby preventing the wire connecting sleeve 2202 from being rotated along with the rotation of the boring rod 12 during excavation.
Further, the stabilizer 28 in the present invention is not limited to the type provided on the outer periphery of the wire connection sleeve 2202. For example, as shown in FIG. 6, a plurality of stabilizers 28 for suppressing the rotation of the casing shoe 18 can be provided on the outer peripheral surface of the casing shoe 18 at regular intervals along the circumferential direction.

  The bit tip conduit 24 stabilizes the digging direction of the drill bit 16 during drilling, and has a length of about 1 m to 5 m and an outer diameter of the third cylindrical portion 1806 of the casing shoe 18. doing. The bit tip conduit 24 is concentrically disposed along the length of the boring rod 12 on the outer periphery of the boring rod 12, and one end thereof is connected to the third cylindrical portion 1806 by screw connection.

  In the present embodiment, the casing shoe 18, the wire connecting sleeve 2202, and the bit tip conduit 24 are arranged on the outer periphery of the bit adapter 14, and one end in the axial direction rotates to the drill bit 16 and rotates around the axis of the drill bit 16. An outer member is constructed which is connected in such a way that it is immovable in the axial direction of the drill bit 16.

Next, a method for placing a ground anchor on a natural ground using the ground anchor placing apparatus 100 configured as described above will be described with reference to FIG.
First, as shown in FIG. 5A, one end of a plurality of wire ropes 20 drawn out from the wire rope bundle 20A is engaged with the connection hole 2204 of the wire connection sleeve 2202 by the connection fitting 26, and the wire rope 20 is attached. The wire connection sleeve 2202 is connected. The ground anchor placing device 100 in such a state is attached to a drilling machine (rotary percussion) 300.

  Next, the rotary impact mechanism 32 and the push-in mechanism 34 are driven in a state where the tip of the drill bit 16 of the ground anchor placing device 100 mounted on the hole drilling machine 300 is pressed against the outer surface of the earth retaining wall 42. When the rotary striking mechanism 32 and the pushing mechanism 34 are driven, the pushing force by the pushing mechanism 34 and the rotation and the striking force by the rotating striking mechanism 32 are transmitted to the drill bit 16 through the boring rod 12 and the bit adapter 14. Thereby, the earth retaining wall 42 is excavated. As shown in FIG. 5A, the drilling bit 16 penetrating the retaining wall 42 pierces the ground 44 with the pushing force by the pushing mechanism 34 and the rotation and the hammering force by the rotary striking mechanism 32, and the hole 46. Form. At the same time, the plurality of wire ropes 20 connected to the wire connection sleeve 2202 are sequentially drawn into the holes 46 formed as the drilling proceeds by the pressing force of the pressing mechanism 34 (the drilling pull-in described in the claims) Corresponding to the process).

  At this time, drill water is supplied from the water supply port 3202 of the rotary impact mechanism 32 to the drill bit 16 through the hollow portion 1206 of the boring rod 12 and the axial hole 1402 of the bit adapter 14, and the drill bit 16 is drilled from the drill water outlet 1604. To the surface. The ground dust (slime) excavated by the drilling bit 16 is drilled by the drilling water supplied to the drilling bit 16, and the inner surface of the drilling bit 16, the casing shoe 18, the connecting member 22 and the drilling hole 44. It flows out into the hole 46 together with the perforated water through the gap generated between the peripheral surface and is discharged out of the hole 46 from the hole 46.

  If a hole 46 having a desired fixed length (for example, about 10 m to 20 m) is formed in the natural ground 44, the boring rod 12 is drilled by the rotary hitting mechanism 32 as shown in FIG. By rotating in reverse, the engagement between the bit adapter 14 and the drill bit 16 is released, and the bit adapter 14 is pulled out from the drill bit 16 to separate them. Thereafter, the pushing mechanism 34 is operated in the direction opposite to the pushing direction while leaving the drill bit 16, the casing shoe 18, the wire connecting sleeve 2202 and the wire rope 20 in the hole 46. Thereby, while pulling out the boring rod 12 including the bit adapter 14 from the hole 46, the hollow space 1202 of the boring rod 12 is passed through the hole 46, the inner space of the drill bit 16, the inner space of the casing shoe 18, and the wire connection sleeve 2202. The grout 48 is pressurized and injected into the internal space (corresponding to the grout injection step described in the claims).

  When the grout injection process is completed, the wire rope 20 is tensioned by the tension jack 36 as shown in FIG. Thereafter, as shown in FIG. 5D, the wire rope 20 is separated from the wire rope bundle 20A. Then, the wire rope 20 is fixed and fixed by the fixing plate 38. Thereby, a ground anchor can be driven in a natural ground.

  In addition, since the length of the rod 1202 to be added as the drilling progresses is about 4.6 m, the drilling is interrupted when drilling about 4 m, and the base end of the rod 1202 is separated from the adapter of the drilling machine. Thereafter, the boom of the drilling machine is returned to the original position, and the rod 1202 to be added is attached to the boom. The rod 1202 to be added is coupled to a rod that has already been drilled to resume drilling. Thereafter, the above operation is repeated to drill to a predetermined depth. Then, after drilling to a predetermined depth, the drilling bit 16 and the bit adapter 14 are separated by rotating the boring rod 12 in the direction opposite to the rotation at the time of drilling, and the boring rod 12 and the bit adapter 14 are recovered. The perforated bit 16, the casing shoe 18, the wire connecting sleeve 2202, and the bit tip conduit 24 are buried in the perforated hole.

According to the ground anchor placement device and the placement method shown in the first embodiment, the drilling bit 16 is used to apply the rotation and impact force to the boring rod 12 and to apply the pushing force. Drill to a certain depth while drilling. At the same time, the wire rope 20 is sequentially drawn into the perforated hole 46. After completion of drilling in the natural ground, the bit adapter 14 is separated from the drill bit 16 by rotating the boring rod 12 in the reverse direction of drilling. The hollow portion 1202 of the boring rod 12 is pulled out while the boring rod 12 including the bit adapter 14 is pulled out from the hole 46 with the perforated bit 16, the casing shoe 18, the wire connecting sleeve 2202 and the wire rope 20 left in the hole 46. Then, grout is pressurized and injected into the hole 46, the inner space of the drill bit 16, the inner space of the casing shoe 18, and the inner space of the wire connecting sleeve 2202.
Therefore, a simple structure such as providing outer members (casing shoe 18, wire connecting sleeve 2202 and bit tip conduit 24) allows a wire rope to be drilled in a hole drilled while drilling a hole for ground anchor placement in a natural ground. It can be inserted and fixed at the same time. As a result, the conventional wire rope insertion process is reduced, and the conventionally used outer tube becomes unnecessary.
In addition, the number of execution steps required for placing the ground anchor can be reduced, and the efficiency and cost of placing can be reduced.
Moreover, since the casing shoe 18 is rotatably connected to the perforated bit 16 and the wire connecting sleeve 2202 is rotatably connected to the casing shoe 18, even if the boring rod 12 is rotated, the wire rope 20 is attached thereto. There is no entanglement, and the wire rope 20 can be inserted stably and reliably simultaneously with the drilling.

  In addition, according to the first embodiment, the conventionally used outer tube is not required, so that the dusting can be discharged inside and outside the drill bit. Along with this, the boring rod 12 is not tightened by dusting as in the conventional outer tube, the boring rod 12 can be easily recovered, and the installation workability can be improved. In addition, since drilling can be performed by rotating and striking only the boring rod 12, it is possible to perform the setting work even if the capacity of the drilling machine is small, and the boring rod 12 can be pulled out by the drilling machine.

In addition, according to the first embodiment, since the bit tip conduit 24 extending to the base end side of the boring rod 12 is connected to the casing shoe 18, the digging direction of the drill bit 16 at the time of drilling is stabilized. It can be made.
Furthermore, according to the first embodiment, since the stabilizer 28 provided in the wire connection sleeve 2202 is engaged with the inner peripheral portion of the drilled hole, the wire connection sleeve 2202 accompanying the rotation of the boring rod 12. , And the tangling of the wire rope 20 to the boring rod 12 can be prevented.

(Second Embodiment)
Next, another example of the wire rope connection method in the ground anchor placing apparatus of the present invention will be described with reference to FIG.
In FIG. 7, the same reference numerals are given to the same or similar parts as in FIG.

The difference from FIG. 1 is that, as is apparent from FIG. 7, the connecting mechanism 22 of the two wire ropes 20 used for placing the ground anchor is configured using a bit-end conduit 24.
For this purpose, the connecting mechanism 22 shown in the second embodiment is provided with wire hooks provided at a plurality of positions spaced 180 degrees in the circumferential direction of the outer peripheral portion of the bit tip conduit 24 connected to the casing shoe 18. Part 2206, and a fastening band 2208 that fastens and fixes the end of each wire rope 20 hooked to each wire hooking part 2206 to the outer peripheral part of the bit tip conduit 24.
Also in the ground anchor placing device using such a coupling mechanism 22, the same effect as that shown in the first embodiment can be obtained.

(Third embodiment)
Next, a modified example of the method of connecting the wire rope to the wire connecting sleeve in the ground anchor placing device of the present invention will be described with reference to FIGS.
In the third embodiment, as shown in FIGS. 8 and 9, after the end portion 20a of the wire rope 20 is inserted into the connection hole 2204 of the wire connection sleeve 2202 from the side opposite to the female screw 2202a, the insertion end portion is inserted. 20a is bent in a U shape, and the bent end portion 20b is inserted into the adjacent connecting hole 2204 from the female screw 2202a side. Thereby, the wire rope 20 can be connected to the wire connection sleeve 2202.
Also in the ground anchor placing device using such a wire rope connection method, the same effect as that shown in the first embodiment can be obtained.

(Fourth embodiment)
Next, still another example of the wire rope connection method in the ground anchor placing apparatus of the present invention will be described with reference to FIG.
In the fourth embodiment, as shown in FIG. 10, a hook fitting 34 for connecting one end 20 b of the wire rope 20 to the connection hole 2204 of the wire connection sleeve 2202 is provided.
The hook fitting 34 has a U-shaped cross section, and has a length L larger than the inner diameter of the connection hole 2204 and a height D smaller than the inner diameter of the connection hole 2204.
When such a hook 34 and one end 20b of the wire rope 20 are coupled, one end 20b of the wire rope 20 is inserted into a U-shaped groove of the hook 34 in a direction perpendicular to the length direction of the hook 34. Plug in. And the one end 20b of the wire rope 20 and the hook metal fitting 34 are connected so that rotation is possible by the coupling pin 36 which penetrates the one end 20b of the wire rope 20 and the hook metal fitting 34.

When connecting such a wire rope 20 to the wire connection sleeve 2202, first, the hook metal fitting 34 is rotated around the coupling pin 36, and the hook metal fitting 34 is connected to the wire rope 20 as shown by an imaginary line in FIG. 10. Hold in a state that matches the length direction. The wire rope 20 in this state is inserted together with the hook metal fitting 34 until it protrudes from the insertion opening 2204a side of the connection hole 2204 to the female screw 2202a side. Thereafter, the hook metal fitting 34 is rotated to the state shown by the solid line in FIG. Then, by pulling the wire rope 20 in this state in the direction of the arrow X in FIG. 10, both ends in the length direction of the hook metal fitting 34 are locked to the edge portion of the connection hole 2204. As a result, the wire rope 20 is connected to the wire connection sleeve 2202.
Also in the ground anchor placing apparatus using such a wire rope connection method, the same effect as that shown in the first embodiment can be obtained.

Next, when the ground anchor is driven by the ground anchor driving device and the driving method described above to improve the ground of the soft ground layer and the ground is reinforced, for example, the tunnel 50 is to be excavated. The case where the natural ground 52 and the face 54 to reinforce are reinforced is demonstrated with reference to FIG.11 and FIG.12.
As shown in FIGS. 11 and 12, rotation and striking force are applied to the boring rod of the ground anchor placing device shown in FIG. 1 at a plurality of portions of the face 54 corresponding to the upper half of the cross section of the tunnel 50. A pressing force is applied to drill a natural ground with a drilling bit along the extending direction of the tunnel 50 to a certain depth. At the same time, the wire rope 2002 connected to the perforated bit through the casing shoe and the connecting mechanism is sequentially drawn into the perforated hole. After the drilling of the face 54 is completed, the boring rod is rotated in the reverse direction to the drilling to separate from the drill bit. Then, the grout is pressure-injected through the boring rod while the boring rod is pulled out from the hole while the drill bit, the casing shoe, the coupling mechanism, and the wire rope 2002 are left in the hole. As a result, the wire ropes 2002 are driven at a plurality of locations of the face 54 shown in FIGS. 11 and 12, and the face 54 is reinforced.

  Similarly, a plurality of ground mountains 52 corresponding to the periphery of the face 54 are drilled obliquely upward away from the inside of the tunnel 50 using the ground anchor placing device shown in FIG. Dig up. At the same time, the wire rope 2004 connected to the perforated bit through the casing shoe and the connecting mechanism is sequentially drawn into the perforated hole. After the drilling of the natural ground is completed, the boring rod is rotated in the reverse direction of the drilling to separate from the drill bit. Then, the grout is pressurized and injected through the boring rod while the boring rod is pulled out from the hole while leaving the drill bit, the casing shoe, the coupling mechanism and the wire rope 2004 in the hole. As a result, the wire rope 2004 is driven at a plurality of locations of the natural ground 52 shown in FIGS. 11 and 12, and the natural ground 52 corresponding to the periphery of the face 54 is reinforced.

Next, as shown in FIG. 12, the reinforced face 54 is excavated using an excavating machine (not shown) while breaking the wire ropes 2002 and 2004, and the entire cross section of the tunnel 50 is extended in the extending direction of the tunnel 50. Drill along. As a result, a tunnel cavity 5002 is formed.
In this case, the wire rope 2002 is hung from the front surface of the face 54 without being cut.
These hanging wire ropes 2002a are cut using a mechanical cutter or a gas cutter, and removed so as not to hinder the face excavation work.

In FIG. 12, the residual wire rope 2002A parallel to the wire rope 2002 and the residual wire rope 2002A parallel to the wire rope 2004 are wire ropes that have been driven one stage before the wire ropes 2002 and 2004 are driven. This is the cable bolt left when the face is excavated by the excavating machine.
In FIG. 12, reference numeral 56 denotes sprayed concrete sprayed on the inner peripheral wall surface of the tunnel 50 after excavation, and reference numeral 58 supports the inner peripheral surface of the tunnel 50 after being covered with the shot concrete 56. 60 is an invert placed on the bottom surface of the tunnel 50.

  By placing the wire rope using the ground anchor placing device and the placement method as described above, the ground of the soft ground layer can be improved and the ground can be reinforced, and the ease of wire rope construction and This is advantageous for improving efficiency.

DESCRIPTION OF SYMBOLS 100 ... Ground anchor placement apparatus 12 ... Boring rod 14 ... Bit adapter 16 ... Drilling bit 18 ... Casing shoe 20 ... Wire rope 22 ... Connection mechanism 2202 ... Wire connection sleeve 24 ... Bit ahead conduit 28 …… Stabilizer 30 …… Removal mechanism

Claims (10)

A hollow boring rod to which rotation and striking force are applied for drilling into the natural ground,
A bit adapter provided at the tip of the boring rod so as to coincide with the axis of the boring rod and move in the axial direction of the boring rod and rotate integrally with the boring rod;
A perforated bit provided by aligning the axis of the bit adapter with the axis of the bit adapter at the tip of the bit adapter;
The bit adapter and the perforated bit cannot be moved in the axial direction of the bit adapter and can be integrally rotated and separable, and the bit adapter and the perforated bit are separated from each other by operation from the base end side of the boring rod. A detachable mechanism;
One end of the axial direction of the bit adapter arranged on the outer periphery of the bit adapter is connected to the perforated bit so as to be rotatable about the axis of the perforated bit and immovably movable in the axial direction of the perforated bit. An outer member formed with an outer diameter to be inserted;
A coupling mechanism that couples one end of a plurality of wire ropes provided on the outer member and disposed along the length direction of the boring rod ;
The outer member is connected to the drill bit so as to be rotatable about the axis of the drill bit and immovable in the axial direction of the drill bit, and a radial direction of the boring rod connected to the casing shoe. A cylindrical wire connecting sleeve extending outwardly toward the base end side of the boring rod,
A ground anchor placing device characterized by that. Said outer member, prior SL is connected to the casing shoe extends radially inwardly toward the proximal end of the boring rod radially outward and the wire connection sleeve of the boring rod, excavation direction of the drilling bit during drilling ground anchor Da設apparatus according to claim 1, characterized in that it is configured to include a cylindrical bit lead pipe to stabilize the. The connection mechanism is provided at a plurality of locations spaced in the circumferential direction of the inner peripheral portion of the wire connection sleeve.
The ground anchor placing apparatus according to claim 1 or 2 , characterized in that Wire hooking portions are provided at a plurality of locations spaced in the circumferential direction of the outer peripheral portion of the bit tip conduit, and the end of each wire rope is hooked on the wire hook portion and the bit tip conduit is clamped by a fastening band. It is fastened and fixed to the outer periphery of
The coupling mechanism includes the bit tip conduit, the wire hooking portion, and the band.
The ground anchor placing device according to claim 2 . Said outer member, one of claims 1 to 4, characterized in that stabilizer to prevent the rotation of the outer member engages the inner peripheral portion of the pore drilled in the drilling bit is provided 1 The ground anchor placing device according to the item. A bit adapter is provided at the tip of a hollow boring rod, a drill bit is provided at the tip of the bit adapter so as to be separable, and an outer member is connected to the drill bit at the outer periphery of the bit adapter so as to be rotatable around the axis of the drill bit. And
One end of each of the plurality of wire ropes is connected to a plurality of locations spaced in the circumferential direction of the outer member on the radially outer side of the boring rod,
The boring rod is rotated and hitting force is applied, and a pushing force is applied to pierce the ground with the drilling bit, and at the same time, the wire rope is drilled into the hole drilled by the outer member. A perforation pulling process of sequentially pulling into
After the drilling of the natural ground is completed, the bit adapter is separated from the drilling bit, and the bit adapter and the boring rod are removed while leaving the drilling bit, the outer member, and the wire rope in the hole. grout into the hole through the boring rod while pulling the bore and a grouting step of pressure infusion,
Separation of the bit adapter from the drilling bit is performed by rotating the boring rod in the reverse direction of the drilling and then pulling out the boring rod.
A ground anchor placing method characterized by that. The outer member includes a casing shoe connected to the drill bit so as to be rotatable about an axis of the drill bit and immovable in the axial direction of the drill bit;
A cylindrical wire connecting sleeve extending to the base end side of the boring rod on the radially outer side of the boring rod is connected to the casing shell;
A plurality of connection holes to which one end of the wire rope is connected at the radially outer side of the boring rod at a plurality of locations spaced in the circumferential direction of the inner peripheral portion of the wire connection sleeve,
Connection of one end of the wire rope to the outer member is performed by connecting one end of the wire rope to the connection hole.
The method for placing a ground anchor according to claim 6 . Before SL casing shoe, the connecting the extending cylindrical bit destination conduit radially outwardly of the boring rod to the proximal end side of the boring rod, the excavation direction drilling bit during drilling and to stabilize ,
The method for placing a ground anchor according to claim 7 . Connecting one end of the wire rope to the previous Kisotogawa member is performed by connecting one end of the wire rope to the bit destination conduit,
The method for placing a ground anchor according to claim 8 . At the time of drilling, the outer peripheral part of the outer member is engaged with the inner peripheral part of the hole drilled by the drilling bit, and rotation of the outer member is suppressed.
The ground anchor placing device according to any one of claims 6 to 9, wherein

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