JP2009174258A - Excavating method and excavating bit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an excavating method capable of excavating a burrying bore in which a filler is surely and easily injected without embedding in spite of a weak and unstable ground and an anchor member is inserted. <P>SOLUTION: By utilizing a down-the-hole hammer style excavating device provided with a drill body 1 in which a hammer for generating hitting power is fitted, and by utilizing an excavating bit 2 provided with a tublar body 23 covering the drill body, a tublar compaction ring bit 21 which is attached at the front edge of the tublar body and has a compaction tip 26 at the outer peripheral surface, and a main bit 20 which is concentrically fitted to the compaction ring bit and has an air discharge port 20a for discharging a muck, a burrying hole A is excavated without water by rotating the compaction ring bit 21 in the hole and reciprocating in an axial direction at every excavation to a described depth in an unstable ground G of ground E, forming a compaction hole wall Ga by compacting the muck generated by excavation to the hole wall with the compaction tip 26, and excavating by pulling the tublar body 23 in the burrying hole A with the compaction ring bit 21. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an excavation method for a buried hole for anchor burial and a excavation bit suitable for the method.

  Anchored anchors such as anchor dendon are embedded in the sloped ground of mountainous areas where there is a risk of landslide, etc. to prevent disasters such as landslides (disaster prevention), and the sloped ground is reinforced. How to do is known.

Conventionally, in order to embed an anchor member, as described in Patent Document 1, a buried hole (a lower hole) is excavated using a tool for down-the-hole method, and a filler such as cement milk is injected into the buried hole, The anchor member was fixed on the ground by the solidification of the filler.
JP 2004-236490 A

  However, the soft and unstable ground has a problem that the buried hole is buried (collapsed) when inserting the anchor member or injecting the filler.

  Therefore, the present invention has an object to provide an excavation method and an excavation bit that can excavate a buried hole in which a filler can be reliably and easily injected and an anchor member can be inserted without being buried even in a soft and unstable ground. And

  Therefore, the excavation method according to the present invention excavates a buried hole for embedding an anchor member in the ground using a down-the-hole hammer type excavator equipped with a drill body incorporating a piston hammer for generating reciprocating impact force. In the excavation method, a cylindrical body covering the drill body, a cylindrical compacting ring bit attached to the tip of the cylindrical body and having a compacting tip on the outer peripheral surface portion, and concentrically built in the compacting ring bit And a main bit having an air discharge port for discharging a gap, and using the excavation bit, the excavation hole is subjected to anhydrous excavation and excavated to a predetermined depth in the unstable ground in the ground. The consolidation ring bit is rotated and reciprocated in the axial direction in the hole excavated every time, and the gap generated by excavation is pressed against the hole wall with the consolidation tip to form a consolidation hole wall. Te, drilling while pulling the cylindrical body to the burying hole in the consolidation ring bit.

  The drill bit according to the present invention is a drill bit that is attached to a drill body for a down-the-hole method with a built-in piston hammer, and a cylinder that covers the drill body and a cylinder that is attached to the tip of the cylinder. And a main bit that is concentrically incorporated in the compacted ring bit, and the compacted ring bit has a plurality of first excavation tips for excavation at the tip and an outer peripheral surface portion. A plurality of compaction tips capable of pressing a gap caused by excavation against the hole wall, and further slidably and rotatably attached to the tip of the cylindrical body by a predetermined stroke, and the main bit is attached to the tip , Having a discharge port for air discharge and a plurality of second excavation tips for excavation, and is pulled out from the compacting ring bit and the cylindrical body in the axial direction and is incorporated so as to be removable. It is those who are.

  According to the excavation method and excavation bit of the present invention, it is possible to draw a cylindrical body capable of preventing collapse into the excavated buried hole. Collapse (burial) of the excavated hole (buried hole) after completion of excavation can be prevented. That is, the anchor member can be easily inserted and the filler can be injected into the ground having an unstable ground. Anchor members can be embedded even on soft and unstable ground.

Hereinafter, the present invention will be described in detail with reference to the drawings illustrating embodiments.
FIG. 1 is a simplified overall view of an excavator used for the anchor embedding method of the present invention.

  First, the ground E to be excavated is a soft and unstable ground G such as sandy soil near the ground surface, and a deep ground J is a solid ground J such as rock. For example, it is a mountain slope with high risk of collapse or landslide. That is, it is a necessary topography for embedding anchor members such as an uncurtain dong and a steel bar for disaster prevention purposes.

  10 is an excavator used in the down-the-hole hammer method (also referred to as down-the-hole method) and the like, and a thrust force that moves the actuator 11 for generating a rotational force such as an electric motor and a table loaded with the actuator 11 back and forth with a feed motor. A generating feed device 12, a drill main body 1 incorporating a hammer for generating a striking force that reciprocates by air, and a drill bit 2 attached to the tip of the drill main body 1 are provided. The actuator 11 and the feeding device 12 are supplied with electric power from the generator 15 and are operated by the controller 16 for control. The forward movement of the feeder 12 is the excavation direction (the direction of the ground E where the buried hole A is to be formed), and the backward movement is the opposite direction.

  The rotation output shaft of the actuator 11 has an air ventilation path inside. A swivel joint 18 is attached to the rotation output shaft. The swivel joint 18 is connected to the compressor 14 via a flow rate regulator 17. A chuck member 19 is attached to the rotation output shaft. A hollow rod member 13 is connected to the rotation output shaft via a rod joint member. The drill body 1 is connected to the tip of the rod member 13 via a connecting member. A drill bit 2 is attached to the tip of the drill body 1. Further, the rod joint member, the rod member 13 and the connecting member each have a ventilation path for introducing the air of the compressor 14 from the rotation output shaft of the actuator 11 to the drill body 1. Further, the chuck member 19 is capable of gripping the cylindrical body 23 of the excavation bit 2.

  The drill body 1 is a known one called a down-the-hole drill or a down-the-hole hammer, and can transmit the rotational force of the actuator 11 to a drill bit 2 attached to the tip. In addition, it has a piston hammer that reciprocates by the air from the compressor 14 and repeats the striking cycle. In addition, a ventilation path is provided to send high-pressure air from the compressor 14 to the excavation bit 2 attached to the tip.

The drill bit 2 will be described. 2 and 3 are cross-sectional side views of the main part of the excavation bit 2. FIG. FIG. 4 shows a front view.
The excavation bit 2 is concentric with the consolidation ring bit 21, a cylindrical body 23 that covers the drill body 1 in the circumferential direction, a consolidated ring bit 21 that is attached to the tip of the cylindrical body 23 via a tubular connecting member 22, and And a main bit 20 incorporated in a shape.

  The cylindrical body 23 has a pipe shape (cylindrical shape) that is long in the axial direction so as to cover the circumference of the drill body 1. A circular pipe member having an inner flange at the tip is welded concentrically to the pipe member, thereby forming an annular groove 23a that is recessed radially outward in the tip.

  The connecting member 22 has a cylindrical shape. Further, the base end has a small flange portion 22b that is loosely fitted in the annular groove 23a of the cylindrical body 23. Further, the outer peripheral surface on the front end side has a male thread portion 22a that is screwed into the consolidation ring bit 21. Also, when the annular groove 23a of the cylindrical body 23 is formed by welding a circular pipe member to a pipe member, the small collar portion 22b is rotatably and slidably mounted (connected to the cylindrical body 23). It is. A cylindrical body 23 is attached concentrically to the tip.

  The connecting member 22 has a difference between the axial length of the annular groove 23a and the axial length of the collar 22b in a state where the small flange 22b is loosely fitted in the annular groove 23a of the cylindrical body 23. The length of the interval formed by is set as a predetermined stroke S and is slidable in the axial direction. Further, it is loosely fitted into the annular groove 23a without being restricted in the circumferential direction. That is, it is attached concentrically to the cylinder 23 so as to be slidable and rotatable.

  The consolidation ring bit 21 has a cylindrical shape. Further, a female screw portion 21d that is screwed into the male screw portion 22a of the connecting member 22 is provided inside the base end. The connecting member 22 is screwed onto the tip. Further, it is fixed by brazing after screwing. It is attached concentrically to the tip of the connecting member 22. That is, the consolidation ring bit 21 is slidably and rotatably attached to the cylindrical body 23 by a predetermined stroke S via the connecting member 22.

The consolidation ring bit 21 is provided with a plurality of super hard first excavation tips 27 made of a hard metal tip for excavation at the tip.
The first excavation tips 27 are arranged at four locations at equal intervals in the circumferential direction on the surface of the tip portion of the consolidation ring bit 21. The four first excavation tips 27 arranged on the surface of the tip end part are slightly tilted so that each tip end faces the axis of the consolidation ring bit 21. Further, eight points are arranged at equal intervals in the circumferential direction on the inclined surface formed in the chamfered shape of the tip portion of the consolidation ring bit 21. That is, they are arranged at a total of 12 locations.

In addition, the compacting ring bit 21 is provided with a plurality of compacting tips 26 for pressing a gap generated by excavation against the hole (inner) wall of the excavated hole (embedded hole A) on the outer peripheral surface portion. The consolidation tip 26 protrudes outward in the radial direction. The consolidation tips 26 are arranged at predetermined intervals along the circumferential direction and the axial direction. As shown in FIG. 2, they are provided in a staircase shape with their positions shifted obliquely in side view. The step-like consolidation chips 26 are arranged at four locations at equal intervals in the circumferential direction. In other words, the compaction tips 26 are provided at a total of 12 locations on the outer peripheral surface portion.
In the figure, the group of compacting chips 26 includes three compacting chips 26, but may be two or four or more. The group of compacting chips 26 may be provided at two locations facing each other in the diameter direction. Further, the shape of the compacting chip 26 is not limited to a circular button shape, and may be a rectangular shape or an oval shape.

  The consolidation ring bit 21 has an annular locking groove 21b that is recessed radially outward in the middle of the inside. The locking concave groove 21b receives a locking projection 20b formed in the main bit 20 and projecting radially outward, and receives thrust in the axial direction of the main bit 20 at the inner wall. Further, a notch portion penetrating in the proximal direction is formed at a predetermined angular position in the circumferential direction of the inner wall on the proximal end side of the locking groove 21b. When the main bit 20 is at a predetermined rotational angle position in the circumferential direction with respect to the consolidated ring bit 21, the notch is formed so that the locking projection 20 b of the main bit 20 It is formed so that it can be inserted and removed. That is, when the main bit 20 is rotated to a predetermined rotational angle position in the circumferential direction with respect to the consolidated ring bit 21, it can be taken out in the axial direction from the base end side of the consolidated ring bit 21.

  The consolidation ring bit 21 has a locking projection 21c that protrudes radially inward from the base end side of the locking groove 21b. The engaging projection 21c locks the transmission protrusion 20c formed in the main bit 20 in the radial outward direction (in contact with the transmission protrusion 20c), and compresses the rotational force of the main bit 20 into a compaction ring. It is transmitted to bit 21. That is, the consolidation ring bit 21 rotates concentrically in the same direction as the main bit 20.

  The main bit 20 has an intake passage 20f for guiding high-pressure air pumped from the compressor 14 through the drill body 1 from the proximal end side to the distal end side. Further, the base end has a spline portion 20 d that receives the rotational force of the actuator 11 transmitted through the drill body 1. Moreover, it has the engagement notch recessed part 20e formed by notching the spline part 20d. The engagement notch recess 20e prevents the dropout when attached to the drill body 1.

  The main bit 20 has a discharge port 20a at the tip for ejecting air from the intake passage 20f in the tip direction and radially outward direction. The discharge port 20a discharges the gap (dusting) generated by excavation from the bottom of the excavated hole (buried hole A) to the outside of the ground (ground E). It is provided at two locations so as to face each other in the diameter direction. Note that three or more discharge ports 20a may be provided.

  The main bit 20 has at its tip two super hard second excavation tips 28 made of cemented carbide tips for excavation at the tip and four points at a chamfered slope formed at the tip. Yes. There are six second excavation tips 28 in total.

Next, the excavation method of the present invention and the method (action) of using the excavation bit 2 suitable for the method will be described with reference to the drawings. FIG. 5 is a simplified explanatory diagram of the process of consolidating the hole wall. FIG. 6 is a simplified explanatory diagram of a process of embedding an anchor member.
As shown in FIG. 1, the excavator 10 is installed in the vicinity of a sloped ground E in a mountainous region having an unstable ground G having a small N value of sandy soil and an unstable ground J. The excavator 10 is installed on a gantry that can swing from a horizontal shape to a downwardly inclined shape. The compressor 14 and the generator 15 for the excavator 10 are installed on a stable ground. A drill bit 2 is attached to the tip of the drill body 1. The cylindrical body 23 of the drill bit 2 covers the outer periphery of the drill body 1. When the generator 15 is started, the compressor 14 starts and high-pressure air is supplied to the drill body 1 and the drill bit 2. The controller 16 operates the actuator 11 and the feeding device 12 to start excavation.

  The main bit 20 is transmitted with the rotational force of the actuator 11, the thrust of the feeder 12, and the striking force of the piston hammer built in the drill body 1.

  When the actuator 11 rotates, the main bit 20 transmits the rotational force of the actuator 11 to the consolidation ring bit 21. The consolidation ring bit 21 rotates. The connecting member 22 attached to the consolidation ring bit 21 rotates. Since the connecting member 22 is not restricted in the rotational direction with respect to the cylindrical body 23, no rotational force is transmitted to the cylindrical body 23. The cylinder 23 does not rotate. That is, the loss of the rotational force and the retracting force due to the frictional resistance that the cylindrical body 23 receives from the ground E does not occur. Therefore, the rotational force from the actuator 11 is efficiently transmitted to the main bit 20 and the consolidation ring bit 21 that perform excavation work.

When the feed device 12 moves forward, the main bit 20 transmits a thrust force that moves forward in the axial direction of the feed device 12 to the consolidation ring bit 21. The consolidation ring bit 21 advances, and the connecting member 22 advances in the axial direction within a predetermined stroke S. The small flange portion 22 b of the connecting member 22 abuts on the inner side wall on the distal end side of the annular groove 23 a of the cylindrical body 23, thereby transmitting a thrust in the forward direction to the cylindrical body 23. The cylindrical body 23 advances to the hole excavated so as to be drawn (in the buried hole A).
When the feeding device 12 moves backward, the main bit 20 transmits a thrust force that moves backward in the axial direction of the feeding device 12 to the consolidation ring bit 21. The consolidation ring bit 21 moves backward. The connecting member 22 moves back in the axial direction within a predetermined stroke S. The small flange portion 22 b of the connecting member 22 abuts on the inner side wall on the proximal end side of the annular groove 23 a of the cylindrical body 23, thereby transmitting the thrust in the backward direction to the cylindrical body 23. The cylinder 23 moves backward.

  When the piston hammer built in the drill body 1 starts a striking cycle, the main bit 20 transmits the striking force in the axial direction of the piston hammer to the consolidation ring bit 21. The consolidation ring bit 21 receives a striking force that advances in the axial direction. The connecting member 22 moves forward in the axial direction within a predetermined stroke S by an impact force. During excavation, a striking force in the forward direction is transmitted to the cylindrical body 23 when the small flange portion 22b of the connecting member 22 is in contact with the inner wall on the distal end side of the annular concave groove 23a of the cylindrical body 23.

  The second excavation tip 28 of the main bit 20 and the first excavation tip 27 of the consolidation ring bit 21 are first on the ground surface side of the ground E due to the rotational force of the actuator 11 and the striking force of the piston hammer of the drill body 1. The buried hole A is excavated in the unstable ground G. At this time, the diameter of the buried hole A is slightly larger than the outer diameter of the cylindrical body 23.

  In addition, high pressure air whose air pressure is adjusted by the compressor 14 and whose flow rate is adjusted by the flow rate regulator 17 flows into the main bit 20. The air flowing into the main bit 20 is ejected from the discharge port 20a at the tip. The air jetted from the discharge port 20a pumps the gap (pulling) generated by excavation from the bottom of the buried hole A to the rear (outward direction of the ground E). The gap passes through the inside and outside of the cylinder 23 and is discharged from the buried hole A by air. Perform dry excavation to discharge the sludge by air (without using water) (excavation process).

  That is, as shown in FIG. 5A, the unstable ground G is excavated by the main bit 20 and the consolidation ring bit 21. The cylindrical body 23 is pulled into the hole excavated with water (buried hole A) without difficulty.

  Then, as shown in FIG. 5 (b), every time the excavation bit 2 excavates (advances) a predetermined depth (for example, 100 mm to 500 mm) in the unstable ground G, the excavation is temporarily stopped, While the consolidation ring bit 21 is rotated at a lower rotational speed than during the excavation process, the air amount is adjusted as necessary, and the controller 16 reciprocates back and forth in the feed device 12. In the excavated hole (the buried hole A during excavation), the consolidation ring bit 21 rotates and reciprocates back and forth. A compaction tip 26 provided in the compaction ring bit 21 presses and compacts (presses) the compaction hole wall Ga in the hole (inner) wall of the buried hole A during excavation to form a compacted hole wall Ga. Improve the hole wall density. In other words, the compacted hole wall Ga having a low void ratio is formed by reusing the gap of the crushed material generated by excavation (consolidation process). Also, the gap remaining after consolidation is discharged with air.

In other words, in the consolidation process, the rotary hitting excavation by the main bit 20 and the consolidation ring bit 21 is not performed. A gap which is pumped backward (upward) from the hole bottom by high-pressure air ejected from the discharge port 20a of the main bit 20 is formed on the hole wall by a compacting tip 26 provided on the outer peripheral surface of the compacting ring bit 21 rotating at a low speed. Compress (press).
By the consolidation process, the hole wall in the unstable ground G becomes a consolidated hole wall Ga with improved strength. The buried hole A is less likely to collapse. That is, the hole wall in the unstable ground G is reinforced.

  An unstable ground G is excavated with the main bit 20 and the consolidation ring bit 21 in an anhydrous manner to form a consolidation hole wall Ga. That is, the excavation process and the consolidation process are alternately performed (consolidation excavation) while the unstable ground G is submerged. The consolidation ring bit 21 pulls the cylindrical body 23 into the embedded hole A having the consolidation hole wall Ga without difficulty.

  Then, as shown in FIG. 5C, after consolidation excavation of the unstable ground G, the excavation bit 2 excavates to a solid ground J located deeper than the unstable ground G. The consolidation process is omitted in the solid ground J. The buried hole A is excavated to a predetermined depth, and the excavation process is completed.

  Next, as shown in FIG. 6A, after excavation is completed (after the excavation process is completed), the main bit 20 is reversely rotated to a predetermined rotation angle position (drawing position) with respect to the consolidation ring bit 21. . The feed device 12 is retracted, and the drill body 1 is retracted in the axial direction. In FIG. 6, the compaction chip 26 is not shown.

  As shown in FIG. 6 (b), the main bit 20 is pulled out from the consolidation ring bit 21 and the cylindrical body 23 while being integrated with the drill body 1 (while being attached to the drill body 1). In the buried hole A, the cylindrical body 23, the connecting member 22, and the consolidation ring bit 21 are left. That is, a cylindrical (pipe) -shaped protective wall member 30 that prevents the buried hole A from collapsing is formed inside the buried hole A. In other words, by retracting the main bit 20 from the excavation bit 2, the protective wall member 30 having the consolidation ring bit 21, the connecting member 22, and the cylindrical body 23 is formed.

  As shown in FIG. 6 (c), an anchor member 60 such as a steel rod is inserted into the cylinder 23, the connecting member 22 and the consolidation ring bit 21 remaining in the buried hole A (inside the protective wall member 30). And a filler such as cement milk is injected.

  After the actuator 11 is moved forward and the cylinder member 23 is gripped by the chuck member 19, the actuator 11 is moved backward by operating the feeding device 12 before the filler is completely solidified.

  As shown in FIG. 5D, before the filler is completely solidified, the cylindrical body 23 is pulled out from the buried hole A. The consolidation ring bit 21 and the connecting member 22 are pulled out from the embedded hole A integrally with the cylindrical body 23. In the buried hole A, the filler and the anchor member 60 are left. In other words, the protective wall member 30 is pulled out with the feeding device 12 retracted, leaving the filler and the anchor member 60 in the buried hole A.

  The anchor member 60 is fixed (fixed) to the ground E (the unstable ground G and the strong ground J) by the solidification of the filler. The solidified filler has a sufficient strength without mixing a large amount of soil (impurities such as sand and soil) in the vicinity of the buried hole A. This anchor member 60 is used to take disaster prevention measures such as landslides.

  The design of the present invention can be changed. For example, the excavator 10 may be integrated with a vehicle (crawler car or the like). In addition, a pulling hole for attaching a hook or a wire can be formed at the base end of the cylindrical body 23, and when pulling, the chuck member 19 is not pulled out by using a wire or hook or the like. good.

  As described above, the excavation method according to the present invention embeds the anchor member 60 in the ground E using the down-the-hole hammer excavator 10 having the drill body 1 incorporating the reciprocating striking force generating piston hammer. In the excavation method for excavating the buried hole A, a cylindrical body 23 covering the drill body 1, a cylindrical consolidation ring bit 21 attached to the tip of the cylindrical body 23 and having a consolidation tip 26 on the outer peripheral surface portion; Using the excavation bit 2 that is concentrically built in the compacting ring bit 21 and has a main discharge port 20 having a discharge port 20a for discharging a gap, the buried hole A is subjected to anhydrous excavation, In the stable ground G, every time a predetermined depth is excavated, the consolidation ring bit 21 is rotated in the excavated hole and reciprocated in the axial direction, and the excavation caused by the excavation chip 26 is drilled into the hole wall. Press to harden Since the wall Ga is formed and excavated while the cylindrical body 23 is pulled into the buried hole A by the compacting ring bit 21, the inner wall (hole wall) of the buried hole A is held by the cylindrical body 23, and landslide during excavation work, etc. It is possible to work quickly by reducing the fear of Further, it is possible to excavate the buried hole A having the compacted hole wall Ga with a low void ratio that can reliably bury the anchor member 60 in the ground E. That is, the anchor member 60 can be embedded in the soft and unstable ground G such as viscous sandy soil. When the filler is injected or the anchor member 60 is inserted, the buried hole A can be prevented from being buried (collapsed). It is possible to prevent a large amount of earth and sand from collapsing into the filler. That is, the filler is solidified to a desired strength, and the anchor member 60 can be reliably embedded. Further, corrosion due to contamination of the anchor member 60 can be prevented. Even if the actuator 11 is small and has a low output, the cylindrical body 23 can be pulled into the embedded hole A. The excavator 10 can be reduced in size and weight. Further, the friction resistance of the cylindrical body 23 is eliminated, and excavation can be performed with a lightweight device.

  Further, the excavation bit of the present invention is attached to the drill body 1 that covers the drill body 1 and the tip of the cylinder body 23 in the excavation bit that is attached to the drill body 1 for down-the-hole method with a built-in piston hammer. A cylindrical consolidating ring bit 21 and a main bit 20 concentrically built in the consolidating ring bit 21, and the consolidating ring bit 21 has a plurality of first excavating tips 27 for excavation at the tip. And a plurality of compaction tips 26 capable of pressing a gap generated by excavation on the outer peripheral surface portion against the hole wall, and further slidably and rotatably attached to the tip of the cylindrical body 23 by a predetermined stroke S. The main bit 20 has a discharge port 20a for discharging the gap and a plurality of second excavation tips 28 for excavation at the tip, and is pulled out from the compacting ring bit 21 and the cylindrical body 23 in the axial direction. Built-in for easy removal Therefore, it is possible to easily retract the cylindrical body 23 that can prevent the buried hole A from collapsing while excavating. It is possible to prevent collapse (burial) of the drilled hole (buried hole A) after completion of excavation. That is, the anchor member 60 can be easily inserted into the ground E having the unstable ground G and the filler can be injected. The anchor member 60 can be embedded even if the N value of the clay sandy soil is 5 or less. Further, it is possible to excavate the buried hole A having the high-strength consolidated hole wall Ga in which the anchor member 60 can be reliably buried in the ground E. The cylinder 23 can excavate the frictional resistance received from the ground E without affecting the main bit 20 and the consolidation ring bit 21 that are excavated. That is, loss of rotational force (torque) and impact force can be reduced. Even if the actuator 11 is small and has a low output, the cylindrical body 23 can be pulled into the embedded hole A. Moreover, since the gap is discharged by air, excavation can be performed without using a liquid such as water. In other words, the construction method using anhydrous water becomes possible, and the nature of the soil can be grasped in detail. Quickly discover groundwater trends. It is possible to prevent the filler from being diluted with pressurized groundwater. Further, it is possible to prevent a large amount of impurities from being mixed in the filler for fixing the anchor member 60, and to reliably embed the anchor member 60 with an appropriate hardness.

1 is a simplified overall view of an excavator used in an excavation method according to the present invention. It is a principal part cross-sectional side view of the excavation bit of this invention. It is a principal part cross-sectional side view of the excavation bit of this invention. It is a front view of the excavation bit of the present invention. It is a simplified explanatory drawing of the process of consolidating a hole wall. It is a simplified explanatory drawing of the process of embedding an anchor member.

Explanation of symbols

1 Drill body
2 Drilling bit
10 Drilling rig
20 main bits
20a Discharge port
21 Consolidation ring bit
23 Tube
26 Compaction tip
27 First drilling tip
28 2nd drilling tip
60 Anchor member A Buried hole E Ground G Unstable ground Ga Consolidated hole wall S Predetermined stroke

Claims (2)

A buried hole for embedding an anchor member (60) in the ground (E) using a down-the-hole hammer excavator (10) equipped with a drill body (1) with a built-in piston hammer for reciprocating striking force In the excavation method for excavating (A),
A cylindrical body (23) covering the drill body (1), and a cylindrical compacting ring bit (21) attached to the tip of the cylindrical body (23) and having a compacting tip (26) on the outer peripheral surface portion; And using the excavation bit (2) provided concentrically in the consolidation ring bit (21) and having a main bit (20) having an air discharge port (20a) for discharging the gap, (A) is subjected to anhydrous excavation, and in the unstable ground (G) in the ground (E), the consolidation ring bit (21) is rotated in the excavated hole every time a predetermined depth is excavated. Reciprocating in the axial direction, pressing the gap generated by excavation into the hole wall with the above-mentioned compaction tip (26) to form a consolidated hole wall (Ga),
An excavation method in which the cylindrical body (23) is excavated while being drawn into the buried hole (A) by the consolidation ring bit (21). In the drill bit attached to the drill body (1) for down-the-hole method with built-in piston hammer,
A cylindrical body (23) covering the drill body (1), a cylindrical compacting ring bit (21) attached to the tip of the cylindrical body (23), and concentric with the compacting ring bit (21) With a built-in main bit (20),
The consolidation ring bit (21) has a plurality of first excavation tips (27) for excavation at the tip, and a plurality of consolidation tips (during the outer peripheral surface that can press the gap generated by excavation against the hole wall ( 26), and is slidably and rotatably attached to the tip of the cylindrical body (23) by a predetermined stroke (S),
The main bit (20) has an air discharge port (20a) for discharging a gap and a plurality of second excavation tips (28) for excavation at the tip, and the consolidation ring bit (21) and the above-mentioned An excavation bit characterized in that it is pulled out from the cylindrical body (23) in the axial direction and is detachable.

Images