Drilling method

Abstract

To provide a drilling method capable of efficiently correcting hole curvature when drilling a hole in the ground.SOLUTION: The drilling method is a method of drilling a hole (boring hole H) in the ground G using a rotating head (drilling blade 16) fitted at the tip of the rod 12. The method includes the steps of: when the rod 12 tilts during the drilling of a hole, pulling up the rotary head with an expanding bit 30 protruded in the radial direction outward from the rotary head; and excavating the wall of the hole at the opposite side of tilt direction of the rod 12 with the expanding bit 30.SELECTED DRAWING: Figure 4

Description

TECHNICAL FIELD

[0001] The present invention relates to a drilling method.

BACKGROUND ART

[0002] For example, drilling machines such as earth augers that drill holes in the ground during construction of earth retaining walls and piles are known (see, for example, Patent Documents 1 to 3).

[0003] The drilling machine disclosed in Patent Document 1 includes a rod and a drilling head (drilling machine) provided at the tip of the rod. Further, a projection for correcting bending of the hole is provided on the outer peripheral portion of the drilling head. When the hole bends during drilling, the drilling head is first pulled up to the position where the hole starts to bend. Next, in a state where the projection of the drilling head is thrust into the hole wall on the side opposite to the bending direction of the hole, the drilling head is rotated in forward and reverse directions to drill the hole wall, thereby correcting the bending of the hole.

PATENT DOCUMENT 1

PATENT DOCUMENT 2

PATENT DOCUMENT 3

DISCLOSURE OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0004] Although the technique disclosed in Patent Document 1 can correct the bending of the hole as described above, there is room for further improvement in order to efficiently correct the bending of the hole.

[0005] In consideration of the above facts, the present invention aims to efficiently correct the bending of a hole when drilling the hole in the ground.

MEANS FOR SOLVING THE PROBLEMS

[0006] The drilling method according to claim 1 is a drilling method in which a hole is drilled in the ground by a rotating head provided at the tip of a rod, wherein if the rod tilts as the hole is drilled, the rotating head is pulled up with an expanding bit protruding radially outward from the rotating head, and the hole wall on the opposite side of the rod's tilt direction is excavated by the expanding bit. Furthermore, the hole wall in the direction of the rod's inclination is not excavated. .

[0007] According to the drilling method of claim 1, if the rod tilts as the hole is drilled, the rotating head is pulled up with the diameter-expanding bit protruding radially outward from the rotating head, and the hole wall on the opposite side of the rod's tilt is excavated with the diameter-expanding bit.

[0008] In this way, the curvature of the drilled hole is corrected by excavating the hole wall on the opposite side of the rod's inclination direction (hereinafter referred to as the "opposite hole wall") with an enlarged bit.

[0009] Furthermore, by tilting the rod and extending the diameter-expanding bit radially outward from the rotating head, the axial rigidity of the rod presses the diameter-expanding bit against the opposite hole wall when drilling the opposite hole wall with the diameter-expanding bit. This allows the diameter-expanding bit to efficiently drill the opposite hole wall. Therefore, the present invention can efficiently correct the curvature of the hole.

[0010] The drilling method of claim 2 is the drilling method of claim 1, After lifting the rotating head, the procedure of pushing down the rotating head, rotating the rotating head in reverse or forward direction, and then lifting the rotating head again while the enlarged bit is engaged with the hole wall of the hole is repeated, The diameter-enlarging bit is used to excavate the hole wall of the hole on the side opposite to the direction of inclination of the rod.

[0011] According to the drilling method of claim 2, the opposite hole wall is drilled with an enlarged bit while rotating the rotating head in both forward and reverse directions. This allows the opposite hole wall to be drilled efficiently with the enlarged bit. Therefore, the present invention makes it possible to correct the curvature of the hole even more efficiently.

[0012] The drilling method of claim 3 is the drilling method of claim 1 or claim 2, wherein if the inclination of the rod with respect to the drilling trajectory of the rotating head is greater than or equal to a predetermined value, the hole wall of the hole on the opposite side of the inclination direction of the rod is excavated with the enlarged diameter bit until the inclination falls below the predetermined value.

[0013] According to the drilling method of claim 3, when the inclination of the rod with respect to the drilling trajectory of the rotating head is greater than or equal to a predetermined value, the opposite hole wall is drilled with an enlarged bit until the inclination of the rod falls below the predetermined value.

[0014] In this way, by drilling the opposite hole wall based on the inclination of the rod relative to the drilling trajectory of the rotating head, the accuracy of correcting the curvature of the hole can be improved. The drilling method of claim 4 is the drilling method of claim 1, wherein the rotating head comprises a plurality of drilling blades arranged in multiple stages, and each of the plurality of drilling blades has the enlarged diameter bit formed thereon. [Effects of the Invention]

[0015] According to the present invention, when drilling holes in the ground, the curvature of the hole can be efficiently corrected. [Brief explanation of the drawing]

[0016] [Figure 1] This is an elevation view showing an overview of a drilling apparatus for implementing a drilling method according to an embodiment of the present invention. [Figure 2] (A) is an elevation view showing the rod in an inclined position, and (B) is a top view showing a schematic of the drilling blade. [Figure 3] (A) is an elevation view showing the drilling blade in the reverse rotation with the enlarged bit protruding, and (B) is a top view of the drilling blade in the enlarged bit protruding state. [Figure 4] (A) is an elevation view showing the rod pulled up with the enlarged bit protruding, and (B) is a top view. [Figure 5] (A) is an elevation view showing the state of excavating the hole wall of the borehole with an enlarged bit, and (B) is a top view. [Figure 6](A) is an elevational view showing another state in which the hole wall of a borehole is being drilled by a reaming bit, and (B) is a top view. [Figure 7] (A) is an elevational view showing a state in which the inclination of the rod and the bending of the borehole are corrected, and (B) is a plan view. [Mode for Carrying Out the Invention]

[0017] Hereinafter, the boring method according to the embodiment of the present invention will be described with reference to the drawings. Components indicated by the same reference numerals in each drawing mean the same components. However, unless otherwise specified in the specification, each component is not limited to one, and a plurality of components may be present.

[0018] In addition, descriptions of overlapping configurations and reference numerals in each drawing may be omitted. The present disclosure is not limited to the following embodiments, and can be implemented with appropriate modifications such as omitting configurations, replacing with different configurations, and combining one embodiment and various modified examples within the scope of the purpose of the present disclosure.

[0019] <Boring Device> FIG. 1 shows a boring device 10 for executing the boring method according to one embodiment of the present invention. The boring device 10 is formed to include a rod 12, a screw 14 provided on the outer peripheral surface of the rod 12, an excavating blade 16 provided at the tip of the rod 12, and an excavating blade 18 provided above the excavating blade 16.

[0020] The excavating blade 16 is an example of the rotary head in the present invention, and is also referred to as an auger head or the like. By rotating the excavating blade 16, the bit 16A of the excavating blade 16 scrapes off the ground G, and a borehole H is formed in the ground G. The bit 16A has a blade formed facing downward.

[0021] On the other hand, the drilling blade 18 is an auxiliary blade provided to complement the drilling performance of the drilling blade 16, and is equipped with a bit 18A with a downward-facing blade, similar to the drilling blade 16. Thus, in this embodiment, the drilling blades are arranged in multiple stages.

[0022] The screw 14 is a discharge mechanism that sends the soil excavated from the ground G by the excavation blades 16 and 18 to the surface.

[0023] In Figure 1, the borehole H is formed approximately vertically. However, if the soil composition of the ground G is uneven and there are hard areas in the drilling direction, the rod 12 may tilt as the borehole H is drilled.

[0024] If drilling is carried out with the rod 12 tilted, the borehole H will be curved. For example, in the example shown in Figure 2(A), the center line CL of the rod 12 is tilted by an angle θ with respect to the design drilling trajectory H1 of the drilling blade 16 (for example, the vertical direction), which is shown by the dashed line. As a result, the borehole H drilled by the tilted rod 12 is also formed with a curve of an angle θ.

[0025] To correct the curvature of the borehole H, a tilt detection device 20 is attached to the rod 12. In addition, an enlarged diameter bit 30, as shown in Figure 2(B), is formed on the drilling blade 16.

[0026] The enlarged bit 30 can have blades formed facing downwards, similar to bit 16A, but it is preferable that the blades be formed facing upwards. Alternatively, it may have a double-edged configuration with blades on both the upper and lower sides.

[0027] Furthermore, an enlarged diameter bit 30 is also formed on the drilling blade 18. The enlarged diameter bit 30 provided on the drilling blade 18 has the same configuration as the enlarged diameter bit 30 provided on the drilling blade 16, so a detailed explanation is omitted.

[0028] The tilt detection device 20 is fixed to the tip and outer surface of the rod 12 and is a device that detects the angle θ of the rod 12 with respect to the vertical direction. The worker operating the drilling device 10 can see the angle θ detected by the tilt detection device 20 from the ground via a monitor or the like.

[0029] The tilt detection device 20 is positioned at different locations in the circumferential direction of the rod 12, depending on the rotation angle of the rod 12. Therefore, the angle θ will be a different value depending on the rotation angle of the rod 12, but the tilt detection device 20 can also detect this rotation angle. This allows the operator to understand in three dimensions which direction and by how much the rod 12 is tilted.

[0030] Note that the rotation angle of the rod 12 does not necessarily need to be detected by the tilt detection device 20. For example, a mark can be placed on the upper end of the rod 12. Preferably, this mark is placed at the same position as the fixed position of the tilt detection device 20 (the position in the circumferential direction of the rod 12). By visually confirming this mark, the rotation angle of the rod 12 can be determined.

[0031] The diameter-enlarging bit 30 is an enlarged blade that can rotate around the rotary hinge 32, and is housed in the drilling blade 16 while the drilling blade 16 is rotating in the direction indicated by arrow N1 in Figure 2(B) (hereinafter referred to as forward rotation).

[0032] On the other hand, when the drilling blade 16 rotates in the direction indicated by arrow N2 in Figure 3(B) (hereinafter referred to as reverse rotation), the tip of the diameter-expanding bit 30 catches on the hole wall of the drilling hole H, and the diameter-expanding bit 30 rotates around the rotary hinge 32 and protrudes radially from the drilling blade 16.

[0033] <Drilling Method> When drilling the borehole H, the drilling blades 16 and 18 are rotated forward in the direction indicated by arrow N1 in Figures 2(A) and (B). As described above, when the drilling blade 16 is rotating forward, the enlarged bit 30 is housed in the drilling blade 16, and the ground G is drilled forward.

[0034] Then, if the rod 12 tilts as the borehole H is drilled, the drilling blades 16 and 18 are rotated in the opposite direction, as shown by arrow N2 in Figures 3(A) and (B), causing the enlarged bit 30 to protrude radially outward from the drilling blades 16 and 18. The enlarged bit 30 catches on the hole wall of the borehole H and bites into the hole wall.

[0035] Here, "when the rod 12 is tilted" means that the tilt detection device 20 detects that the tilt of the rod 12 with respect to the drilling trajectory H1 exceeds a predetermined value. Alternatively, it means that a worker confirms the tilt of the rod 12 detected by the tilt detection device 20 and determines that the tilt is above a predetermined value.

[0036] The hole wall into which the enlarged bit 30 protrudes and bites is the hole wall on the opposite side of the direction of inclination of the rod 12 (i.e., the direction in which the inclination is greater than or equal to a predetermined value).

[0037] In Figure 3(B), the direction indicated by arrow M (the direction in the plan view) when viewed from the center O of the rod 12 is the direction of inclination of the rod 12. Also, the hole wall located in the direction obtained by rotating arrow M 180° from the center O of the rod 12, and the hole walls around it, are the opposite hole walls.

[0038] In this diagram, the diameter-expanding bit 30 is embedded in the hole wall located in the direction of arrow M rotated 180° from the center O of the rod 12. The position on the plane where the diameter-expanding bit 30 is embedded will be referred to as position K1 in the following explanation.

[0039] Next, as shown by arrow N4 in Figures 4(A) and (B), with the diameter-expanding bit 30 embedded in the hole wall of borehole H, the drilling blades 16 and 18 are pulled up. At this time, the drilling blades 16 and 18 are pulled up without rotating. As a result, as shown by arrow N5, the diameter-expanding bit 30 is also pulled up, and the hole wall of borehole H is drilled.

[0040] Although the tip of the rod 12 is inclined with respect to the drilling track H1, the angle of the rod 12 is adjusted so that it is aligned vertically near the ground surface. As a result, a bending force acts on the rod 12, and at the tip, a bending return force P acts in the opposite direction to the inclination due to the axial stiffness of the rod 12.

[0041] Due to this bending return force P, the enlarged bit 30 is pressed against the hole wall of the borehole H and excavates the hole wall of the borehole H. Since position K1 is 180° from the inclination direction of the rod 12, the largest bending return force P acts at position K1.

[0042] Next, as indicated by arrow N6 in Figures 5(A) and (B), the drilling blades 16 and 18 are pushed down again. Then, after rotating the drilling blades 16 and 18 in the reverse direction as indicated by arrow N7, the drilling blades 16 and 18 are pulled up with the enlarged bit 30 embedded in the hole wall of the borehole H, in the same manner as described in Figure 4(A).

[0043] In this way, by repeating the operations shown in Figures 3 to 5, the hole wall of the borehole H (the region from position K1 to K2) is excavated in the "reverse rotation" direction of the drilling blades 16 and 18, starting from position K1 where the enlarged bit 30 was first inserted. The rod 12 moves toward the excavated region V1, and its tilt is corrected.

[0044] On the other hand, it is also possible to excavate the hole wall of the borehole H in the "forward rotation" direction of the drilling blades 16 and 18, starting from the position K1 where the enlarged bit 30 is first inserted.

[0045] In this case, as shown in Figures 6(A) and (B), the drilling blades 16 and 18 are rotated "forward" as indicated by arrow N8, and then, in the same manner as described in Figure 4(A), the drilling blades 16 and 18 are pulled up with the enlarged bit 30 embedded in the hole wall of the borehole H. This creates the drilled region V2 (the region from position K1 to K3). The rod 12 moves toward the drilled regions V1 and V2 to correct its tilt.

[0046] As described above, the forward rotation and reverse rotation of the drilling blades 16 and 18, the biting of the enlarged bit 30 into the hole wall due to the reverse rotation, the downward movement and upward movement of the drilling blades 16 and 18, and the drilling of the hole wall by the enlarged bit 30 due to the upward movement are performed multiple times in an appropriate combination.

[0047] As a result, as shown in Figures 7(A) and (B), the hole wall opposite to the direction of inclination of the rod 12 is excavated in stages, and the rod 12 moves into the excavated area, correcting its inclination. Consequently, the bending of the rod 12 is corrected.

[0048] <Mechanism and Effects> According to the drilling method according to an embodiment of the present invention, as shown in Figure 2(A), when the rod 12 tilts as the borehole H is drilled, the enlarged bit 30 is made to protrude radially outward from the drilling blades 16 and 18, which act as a rotating head, as shown in Figures 3(A) and (B). Then, as shown in Figure 4(A), while pulling up the drilling blades 16 and 18, the enlarged bit 30 is used to drill the borehole wall of the borehole H on the opposite side of the direction of tilt of the rod 12.

[0049] In this way, the curvature of the borehole H is corrected by excavating the borehole wall opposite to the direction of inclination of the rod 12 with the diameter-enlarging bit 30.

[0050] Furthermore, by tilting the rod 12 and allowing the enlarged diameter bit 30 to protrude radially outward from the drilling blades 16 and 18, the axial rigidity of the rod 12 presses the enlarged diameter bit 30 against the opposite hole wall when drilling the opposite hole wall with the enlarged diameter bit 30. This allows the enlarged diameter bit 30 to efficiently drill the opposite hole wall. Therefore, the present invention makes it possible to efficiently correct the curvature of the drilled hole H.

[0051] Furthermore, according to the drilling method according to the embodiment of the present invention, the opposite hole wall is drilled with the enlarged diameter bit 30 while the drilling blades 16 and 18 are rotated in the forward and reverse directions. This makes it possible to efficiently drill the opposite hole wall with the enlarged diameter bit 30.

[0052] Specifically, according to this drilling method, drilling is first performed at position K1, which is 180° from the direction of inclination, on the opposite side of the hole wall from the direction of inclination of the rod 12. After drilling from position K1 to position K2, the drilling blade 16 is rotated forward, and drilling is performed from position K3 to position K2.

[0053] This allows the hole wall of the borehole H to be excavated from the position where the bending return force of the rod 12 is greatest, resulting in high excavation efficiency. Therefore, in this embodiment, the curvature of the borehole H can be corrected even more efficiently.

[0054] <Other Embodiments> In the above embodiment, as shown in Figure 7(A), an example is shown in which the hole wall of the borehole H is excavated until the inclination of the rod 12 becomes 0° with respect to the drilling trajectory H1 of the drilling blade 16, that is, until the rod 12 is aligned vertically. However, the embodiments of the present invention are not limited to this. For example, the hole wall of the borehole H may be excavated until the inclination of the rod 12 becomes an angle less than a predetermined value with respect to the drilling trajectory H1.

[0055] This "predetermined value" can be set appropriately depending on the intended use of the borehole H. For example, when inserting a precast pile (such as a PHC pile) into the borehole H, the borehole H may have an inclination sufficient to ensure the vertical accuracy required for the precast pile to be inserted. For this reason, the rod 12 may also be inclined according to the allowable inclination of the borehole H.

[0056] In this way, by excavating the opposite hole wall based on the inclination of the rod 12 with respect to the drilling trajectory H1 of the drilling blade 16, the accuracy of correcting the curvature of the borehole H can be improved.

[0057] Furthermore, in the above embodiment, the drilling blade as a rotating head is a multi-stage drilling blade equipped with drilling blades 16 and 18, but the embodiments of the present invention are not limited to this. For example, drilling blade 18 may be omitted. Alternatively, even if drilling blade 18 is present, the diameter-enhancing bit 30 may be omitted from this drilling blade. Also, a diffusion blade may be provided instead of drilling blade 18. The diameter-enhancing bit 30 may or may not be provided for this diffusion blade.

[0058] In other words, in the present invention, it is sufficient to form an enlarged-diameter bit 30 on the drilling blade 16 located at least at the tip of the rod 12. By forming an enlarged-diameter bit 30 on the drilling blade 16, the curvature of the borehole H can be efficiently corrected by the above-described drilling method.

[0059] Furthermore, in the above embodiment, after excavating the opposite side of the borehole wall with respect to the inclination direction from position K1 to position K2, which is 180° with respect to the inclination direction, the drilling blade 16 is rotated forward to excavate from position K3 to position K2 (reverse rotation → forward rotation → reverse rotation). This procedure is repeated to excavate the opposite side borehole wall in stages, but the order of excavation of the opposite side borehole wall is not particularly limited.

[0060] For example, after drilling from position K3 to position K2, the drilling blade 16 can be rotated in the forward direction, and this procedure can be repeated to gradually drill the opposite borehole wall. Even with such a drilling sequence, the curvature of the borehole H can be efficiently corrected. [Explanation of symbols]

[0061] 12 rods 16. Drilling blades (rotating head) 18. Drilling blade (rotating head) 30 Diameter-expanding bit 32-rotation hinge H. Borehole (hole)

Claims

1. In a drilling method in which a hole is drilled into the ground by a rotating head provided at the tip of a rod, If the rod tilts as the hole is drilled, the rotating head is pulled up with the diameter-expanding bit protruding radially outward from the rotating head, and the hole wall on the opposite side of the rod's tilt direction is excavated with the diameter-expanding bit, while the hole wall on the side of the rod's tilt direction is not excavated. Drilling method.

2. After raising the rotating head, the procedure of pushing down the rotating head, rotating the rotating head in the reverse or forward direction, and then raising the rotating head again while the diameter-expanding bit is embedded in the hole wall is repeated, thereby excavating the hole wall of the hole on the opposite side of the rod's inclination direction with the diameter-expanding bit. The drilling method according to claim 1.

3. If the inclination of the rod with respect to the drilling trajectory of the rotating head is greater than or equal to a predetermined value, the hole wall of the hole on the opposite side of the inclination direction of the rod is excavated with the enlarged bit until the inclination falls below the predetermined value. The drilling method according to claim 1 or claim 2.

4. The rotating head comprises a plurality of drilling blades arranged in multiple stages, Each of the aforementioned multiple drilling blades has the aforementioned enlarged diameter bit formed therein. The drilling method according to claim 1.

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