Leak suppression device

Abstract

The present invention provides a leak suppression device that can effectively discharge objects from a borehole during drilling, and suppresses leakage of fluids injected into the ground during fluid injection, thereby enabling effective compaction of the ground. [Solution] The leak suppression device is provided on a drilling machine (10) that drills a hole (5) with a drilling tool (11) comprising a rod (12) and a bit (13), and pressurizes a fluid (F) into the hole (5) from the lower end of the drilling tool (11). Above the bit (13) and on the outer circumference of the rod (12), a fluid retention device (20) is provided. The fluid retention device (20) comprises a case (21) that surrounds the rod (12) and forms an internal space between itself and the rod (12), an inlet opening (25) provided in the case (21) that connects the internal space to the outside of the case (21), and an outlet opening provided above the inlet opening (25) in the case (21) that connects the internal space to the outside of the case (21).

Description

Technical Field

[0001] The present invention relates to a leak suppression device.

Background Art

[0002] Conventionally, as a method for increasing the bearing capacity of the ground and preventing liquefaction, a static compaction method is known (for example, see Patent Document 1). In the static compaction method, the ground is drilled by a bit provided at the tip of a rod, and a fluid composed of low-fluidity mortar or fluidized sand is injected into the ground to compact the ground. Specifically, the fluid injected into the ground from the bit acts to expand the hole wall around the drilling tool composed of the bit and the rod, and exhibits the effect of compacting the ground. At this time, the fluid may rise toward the ground surface through the gap between the drilling tool and the hole wall.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the conventional static compaction method as described above, depending on the fluidity of the fluid and the flow velocity of the fluid, it is conceivable that the fluid injected into the hole in the ground rises and leaks to the ground surface side. In this case, there is a possibility that the effect of compacting the ground by injecting the fluid may be reduced. Also, it is considered that leakage can be suppressed by closing the upper part of the hole in the ground, but in this case, it becomes difficult to discharge the objects in the hole such as drilling water and excavated materials during drilling. Therefore, it is desired that the objects in the hole can be discharged well during drilling, and that leakage of the fluid injected into the ground can be suppressed and the ground can be effectively compacted during injection of the fluid.

[0005] In view of these points, the present invention aims to provide a leak suppression device that can effectively discharge objects from a hole during drilling, suppress leakage of fluid injected into the ground during fluid injection, and enable effective compaction of the ground. [Means for solving the problem]

[0006] The leak suppression device is provided on a drilling machine that drills a hole in the ground using a drilling tool comprising a rod and a bit provided at the lower end of the rod, and presses a fluid into the hole from the lower end of the drilling tool, and the leak suppression device is provided on the outer circumference of the rod above the bit, and the fluid retention device comprises a case that surrounds the rod and forms an internal space between it and the rod, an inlet opening provided in the case that connects the internal space to the outside of the case, and an outlet opening provided in the case above the inlet opening that connects the internal space to the outside of the case.

[0007] Furthermore, the leak suppression device is a leak suppression device provided in a drilling machine that drills a hole in the ground using a drilling tool comprising a rod and a bit provided at the lower end of the rod, and presses a fluid into the hole from the lower end of the drilling tool, wherein a shutter device is provided on the outer circumference of the rod above the bit, and the shutter device comprises a closing member extending radially outward from the outer circumference of the rod to close the hole, a shutter opening that penetrates the closing member in the axial direction of the rod, and an opening / closing member that can open and close the shutter opening. [Effects of the Invention]

[0008] According to the present invention, objects inside the hole can be effectively discharged during drilling, and when a fluid is injected, leakage of the fluid injected into the ground can be suppressed, and the ground can be effectively compacted. [Brief explanation of the drawing]

[0009] [Figure 1]This is a cross-sectional view showing a drilling operation in the ground using a drilling machine equipped with a leak suppression device according to an embodiment of the present invention. [Figure 2] This is a perspective view showing a fluid retention device. [Figure 3A] This is a plan view of the shutter mechanism in the open position, seen from above. [Figure 3B] This is a plan view of the shutter mechanism in the closed position, seen from above. [Figure 4] This is a plan view of the blocking member as seen from above. [Figure 5A] Figure 3A is a plan view showing the opening and closing member in the open state. [Figure 5B] Figure 3B is a plan view showing the opening and closing member in the closed state. [Figure 6] This is a cross-sectional view showing the drilling process in which a drilling machine drills a hole in the ground. [Figure 7] This is a cross-sectional view showing the diameter expansion process in which the lower part of the hole is enlarged. [Figure 8] This is a cross-sectional view showing the injection process in which a fluid is injected into a hole. [Figure 9] This is a cross-sectional view showing the ground after it has been compacted by the press-in process. [Figure 10] This is a conceptual diagram showing a modified example of the embodiment. [Modes for carrying out the invention]

[0010] Hereinafter, an embodiment of the leak suppression device according to the present invention will be described with reference to the attached drawings.

[0011] Figure 1 is a cross-sectional view showing a drilling operation in the ground G by a drilling machine 1 equipped with a leak suppression device 10 according to an embodiment of the present invention. The drilling machine 1 is used in a static compaction method in which a hole 5 is drilled into the ground G, and a fluid F (see Figure 8) is injected into the hole 5 to compact the ground G.

[0012] The hole drilling machine 1 includes a hole drilling tool 11 for drilling a hole 5 in the ground G, a hole drilling tool driving unit (not shown) for driving the hole drilling tool 11, a pumping device (not shown) for pumping the fluid F, and a leak suppression device 10 for suppressing the leakage of the fluid F from the hole 5.

[0013] The hole drilling tool 11 includes a boring rod 12 (rod) that moves in the axial direction and a bit 13 attached to the lower end of the boring rod 12. The hole drilling tool driving unit is, for example, a drill unit disposed on the ground surface side of the ground G, and drills the hole 5 in the ground G with the bit 13 by moving the boring rod 12 in the axial direction (vertical direction) while rotating it.

[0014] The boring rod 12 is a cylindrical pipe. The hole drilling water and the fluid F are supplied to the bit 13 through the flow path inside the cylinder of the boring rod 12.

[0015] The bit 13 includes a cylindrical bit body portion 14, a plurality of diameter-expanding wings 15 provided on the outer peripheral surface of the bit body portion 14, and a drilling tooth 16 provided at the lower end of the bit body portion 14. The bit body portion 14 is cylindrical with a larger diameter than the boring rod 12 and is arranged coaxially with the boring rod 12. The hole drilling water and the fluid F supplied from the flow path of the boring rod 12 to the bit 13 pass through the flow path inside the cylinder of the bit body portion 14 and are supplied to the hole 5 from the discharge port at the lower end of the drilling tooth 16.

[0016] Further, the bit body portion 14 includes a storage recess 14a in which the outer peripheral surface of the bit body portion 14 is recessed radially inward. The storage recesses 14a are provided at a plurality of positions (three positions in the present embodiment) at equal intervals in the circumferential direction of the bit body portion 14.

[0017] The diameter-expanding wings 15 are plate-like members respectively stored in the storage recesses 14a. In the state where the diameter-expanding wings 15 are stored in the storage recesses 14a, one end portion 15a of the diameter-expanding wings 15 in the circumferential direction of the bit body portion 14 is pivotally supported so as to be rotatable. In detail, one end 15a is pivotally supported, and the rotational center axis 15b extending in the axial direction (vertical direction) of the boring rod 12 is located at the end 15a, allowing the diameter-expanding blade 15 to rotate around the rotational center axis 15b. The diameter-expanding blade 15 can be opened and closed by rotating around the rotational center axis 15b, expanding in diameter when open and contracting in diameter when closed. Furthermore, the other end of the circumferentially expanding wing 15 of the bit body 14 is provided with a drilling claw portion 15c.

[0018] The leak suppression device 10 includes a fluid retention device 20 for retaining the fluid F and a shutter device 30 for blocking the hole 5 and suppressing the rise of the fluid F.

[0019] Figure 2 is a perspective view showing the fluid retention device 20. Referring to Figures 1 and 2, the fluid retention device 20 is provided on the outer circumference of the boring rod 12 above the bit 13. The fluid retention device 20 includes a case 21 that surrounds the boring rod 12 and forms an internal space 20a between it and the boring rod 12.

[0020] The case 21 comprises a cylindrical case peripheral wall portion 22 that surrounds the boring rod 12 from all sides, an annular case lower wall portion 23 extending from the lower end of the case peripheral wall portion 22 toward the outer circumferential surface 12a of the boring rod 12, and an annular case upper wall portion 24 extending from the upper end of the case peripheral wall portion 22 toward the outer circumferential surface 12a of the boring rod 12. The case 21 is fixed to the boring rod 12 by the connection of the inner circumference of the lower wall portion 23 and the inner circumference of the upper wall portion 24 of the case to the outer surface 12a of the boring rod 12. The case 21 rotates integrally with the boring rod 12. The internal space 20a is an annular space located inside the case 21, partitioned between the inner surface of the case 21 and the outer surface 12a of the boring rod 12. The outer diameter of case 21 is formed to be the same as the outer diameter of the drilling teeth 16. However, the outer diameter of case 21 may be formed to be smaller than the outer diameter of the drilling teeth 16.

[0021] Furthermore, the case 21 includes a side opening 22a that penetrates the case peripheral wall 22 radially and communicates with the internal space 20a, and an upper opening 24a that penetrates the case upper wall 24 vertically and communicates with the internal space 20a. The side openings 22a are elongated slit-shaped holes that extend vertically from the lower end to the upper end of the case peripheral wall portion 22. Multiple side openings 22a are provided at equal intervals in the circumferential direction of the case 21. The top opening 24a is a slit-shaped elongated hole that extends in a narrow, elongated manner in the circumferential direction of the case 21, along the outer circumference of the case's upper wall portion 24. Multiple top openings 24a are provided at equal intervals in the circumferential direction of the case 21.

[0022] The upper end of the side opening 22a is the upper end opening 22a1. The portion of the side opening 22a below the upper end opening 22a1 (the entire portion excluding the upper end opening 22a1) functions as an inlet opening 25 for allowing drilling water and fluid F to flow into the internal space 20a. Furthermore, the upper end opening 22a1 and the top opening 24a of the side opening 22a function as outlet openings 26 that allow drilling water and fluid F in the internal space 20a to flow out to the outside of the case 21. The sum of the areas of the outlet openings 26 is set to be smaller than the sum of the areas of the inlet openings 25.

[0023] Figure 3A is a plan view of the shutter device 30 in the open state, viewed from above. Figure 3B is a plan view of the shutter device 30 in the closed state, viewed from above. Referring to Figures 1, 3A, and 3B, the shutter device 30 includes a closing member 31 that extends radially outward from the outer circumference of the boring rod 12 and closes the hole 5, and an opening / closing member 40 that is mounted vertically on top of the closing member 31 and is rotatable relative to the closing member 31. The shutter device 30 is positioned above the fluid retention device 20. The outer diameter of the shutter device 30 is formed to be the same as the outer diameter of the drilling teeth 16. However, the outer diameter of the shutter device 30 may be formed to be smaller than the outer diameter of the drilling teeth 16.

[0024] Figure 4 is a plan view of the closing member 31 as seen from above. The closure member 31 comprises a plurality of closure pieces 32 extending radially outward from the outer circumference of the boring rod 12. Multiple closure pieces 32 are provided at equal intervals (three locations in this embodiment) in the circumferential direction of the boring rod 12. Furthermore, the closing member 31 includes shutter openings 33 formed by cutting out the portion between adjacent closing pieces 32 in the closing member 31. Multiple shutter openings 33 are provided at equal intervals in the circumferential direction of the boring rod 12 (three in this embodiment). The shutter openings 33 are holes that penetrate the closing member 31 in the axial direction of the boring rod 12. The blocking member 31 rotates integrally with the boring rod 12.

[0025] Figure 4 shows the forward rotation direction R1 of the boring rod 12 when the boring rod 12 rotates in the forward direction to drill the hole 5, indicated by an arrow. A fixing hole 32a is provided at the end of the closing piece 32 on the R1 side in the forward rotation direction. A rotation restricting member 34 (see Figure 3) is attached to the fixing hole 32a. The rotation restricting member 34 protrudes downward from the closing piece 32 and is connected to the opening / closing member 40. The rotation restricting member 34 is, for example, a bolt that is inserted through the fixing hole 32a from above and screwed into the fixing hole 32a.

[0026] Figure 5A is a plan view showing the opening / closing member 40 in the open state as shown in Figure 3A. Figure 5B is a plan view showing the opening / closing member 40 in the closed state as shown in Figure 3B. Referring to Figures 1 and 3A to 5B, the opening / closing member 40 is positioned below the closing member 31 and overlaps the closing member 31 from below. The outer diameter of the opening / closing member 40 is the same as the outer diameter of the closing member 31. The opening / closing member 40 comprises an annular portion 41 that fits onto the outer circumferential surface 12a of the boring rod 12, a plurality of closing portions 42 extending radially outward from the annular portion 41, a plurality of openings 43 provided between adjacent closing portions 42, and a resistance portion 44 that protrudes in the axial direction of the boring rod 12 relative to the plate-shaped closing portions 42. In the cross-sectional views such as Figure 1, hatching is applied to the opening 43 and the shutter opening 33 for distinction.

[0027] Multiple (three in this embodiment) occlusion sections 42 are provided at equal intervals in the circumferential direction of the boring rod 12. Multiple openings 43 are provided at equal intervals (three in this embodiment) in the circumferential direction of the boring rod 12.

[0028] The opening / closing member 40 has an annular portion 41 that is rotatably fitted onto the outer circumferential surface 12a of the boring rod 12. Therefore, the opening / closing member 40 is rotatable relative to the boring rod 12 and the closing member 31 with respect to the boring rod 12.

[0029] Figures 5A and 5B illustrate the forward rotation direction R1 and the reverse rotation direction R2, which occurs when the boring rod 12 rotates in the opposite direction to the forward rotation direction R1, with arrows indicating the direction of rotation. The resistance portion 44 is a plate-shaped member that extends in the vertical direction. The resistance portion 44 is fixed to the end of the closing portion 42 on the R1 side in the forward rotation direction at its circumferential end. The lower end of the resistance portion 44 is fixed to the end of the closing portion 42 on the R1 side in the forward rotation direction, and the resistance portion 44 protrudes upward from the closing portion 42. In detail, the lower end of the resistance portion 44 is fastened to the circumferential end face of the closing portion 42 by a bolt (not shown) inserted through this lower end. The resistance section 44 is provided in each closing section 42. Therefore, in this embodiment, the resistance section 44 is provided at three locations at equal intervals in the circumferential direction of the opening / closing member 40.

[0030] A groove 45 is provided on the upper surface of the closing portion 42, extending in an arc shape along the outer circumference of the closing portion 42. The groove 45 has one end 45a which is the end on the side of the forward rotation direction R1, and the other end 45b which is the end on the side of the reverse rotation direction R2. One end 45a is open to the outside of the closure portion 42 in the circumferential direction, but is blocked by the resistance portion 44. The other end 45b is a closed end that is closed in the circumferential direction without opening to the outside of the closing portion 42. The lower end of the rotation restricting member 34 (see Figure 3), which is provided on the closing piece 32 of the closing member 31, is positioned within the groove 45.

[0031] The shutter device 30 can be switched between an open state and a closed state by the relative rotation of the opening / closing member 40 with respect to the closing member 31. Figures 1 and 3A illustrate the shutter device 30 in the open state.

[0032] In the open position, the opening / closing member 40 is positioned in a rotational position where the opening 43 overlaps the shutter opening 33 from below. Also in the open position, the closing part 42 overlaps the closing piece 32 from below. Furthermore, in the open state, the rotation restricting member 34 is located on one end 45a side of the groove 45, and the resistance portion 44 is in contact with one end surface 32b of the closing piece 32 in the circumferential direction. As shown in Figure 1, the resistance portion 44 extends upward from the closing piece 32. In the open state, the opening 43 and the shutter opening 33 are in communication, so for example, drilling water can pass through the opening 43 and the shutter opening 33 to the shutter device 30.

[0033] Figure 3B shows the shutter device 30 in the closed state. In the closed state, the opening / closing member 40 is positioned in a rotational position where the closing portion 42 overlaps the shutter opening 33 from below. Also, in the closed state, the opening 43 overlaps the closing piece 32 from below. Furthermore, in the closed state, the rotation restricting member 34 abuts against the other end 45b of the groove 45, and the resistance portion 44 abuts against the other end surface 32c of the closing piece 32 in the circumferential direction. In the closed state, the shutter opening 33 is closed by the closing part 42, so for example, drilling water and fluid F cannot pass through the shutter opening 33 and through the shutter device 30.

[0034] Here, we will explain an example of the process for static compaction using drilling machine 1. Figure 6 is a cross-sectional view showing the drilling process in which a bore is drilled into the ground G by the drilling machine 1. The drilling machine 1 drills the hole 5 by lowering the drilling tool 11 while rotating it in the forward rotation direction R1. As shown in Figure 6, when the drilling tool 11 is rotating in the forward rotation direction R1, one end 15a of the expanding blade 15, where the rotational center axis 15b of the expanding blade 15 is located, is on the side of the direction of travel in the forward rotation direction R1. Therefore, the expanding blade 15 is not subjected to an opening force and is maintained in a state stored in the storage recess 14a.

[0035] During drilling, the drilling water W ejected from the lower end of the bit 13 and the excavated material generated by the drilling of the drilling tool 11 rise above the bit 13 by passing between the outer surface of the drilling tool 11 and the inner surface of the hole 5.

[0036] Referring to Figures 2 and 6, the drilling water W and objects in the hole 5, such as the excavated material, move upward through the space between the outer surface of the fluid retention device 20 and the inner surface of the hole 5. In addition, some of the drilling water W and excavated material flow into the internal space 20a from the side opening 22a of the fluid retention device 20, and move upward through the top opening 24a from the internal space 20a to the fluid retention device 20 (although the drilling water W is not shown in Figure 2, the flow of the drilling water W is the same as that of the fluid F in Figure 2). Furthermore, some of the drilling water W and excavated material in the internal space 20a may be discharged upward through the upper end opening 22a1 of the side opening 22a.

[0037] Referring to Figures 3A and 6, when the drilling tool 11 is rotating in the forward rotation direction R1, the shutter device 30 is in the open state. More specifically, when the drilling tool 11 rotates in the forward rotation direction R1, the opening / closing member 40 receives resistance from the object in the hole 5 via the resistance part 44 and rotates relative to the closing member 31 in the counter-rotation direction R2, causing the shutter device 30 to open. In the open state, the opening / closing member 40 is positioned at a first predetermined rotational position in which the shutter device 30 is in the open state, by having the resistance portion 44 abut against one end surface 32b of the closing piece 32. Here, the object that acts as resistance for the resistance section 44 is the drilling water W and the excavated material. Since the resistance section 44 protrudes upward relative to the closing section 42, it can efficiently receive the resistance of the drilling water W and the excavated material. Therefore, the shutter device 30 can be switched to the open state by utilizing the resistance of the drilling water W and the excavated material. The resistance section 44 may also protrude downward relative to the closing section 42.

[0038] The drilling water W and excavated material moving upward from the fluid retention device 20 side move upward through the space between the outer surface of the shutter device 30 and the inner surface of the hole 5, and through the opening 43 and the shutter opening 33, and are discharged to the outside from the opening at the upper end of the hole 5. In this way, since the shutter device 30 is automatically opened during the drilling process, the drilling water W and excavated material can be discharged to the outside of the hole 5 even with a structure equipped with a shutter device 30.

[0039] Figure 7 is a cross-sectional view showing the diameter expansion stroke in which the lower part of hole 5 is expanded. During the diameter expansion stroke, the drilling machine 1 rotates the drilling tool 11 in the reverse rotation direction R2. When the drilling tool 11 is rotating in the reverse direction R2, the claw portion 15c of the diameter-expanding blade 15 is located on the side of the direction of travel in the reverse direction R2. As a result, the diameter-expanding blade 15 receives an opening force from objects such as excavated material around it. Consequently, the diameter-expanding blade 15 rotates and unfolds in the forward direction R1 around the rotational axis 15b, and the position of the claw portion 15c moves radially outward. The enlarged diameter wing 15 is positioned at a predetermined opening angle when one end 15a abuts against a stopper portion (not shown) provided in the storage recess 14a.

[0040] By rotating the drilling tool 11 in the reverse direction R2 with the diameter-expanding blade 15 extended, the inner circumferential surface of the hole 5 is cut by the claw portion 15c, and an enlarged hole portion 5a is formed at the bottom of the hole 5. Furthermore, by moving the drilling tool 11 upward with the diameter-expanding blade 15 extended, the height of the enlarged hole portion 5a is increased.

[0041] Furthermore, referring to Figures 3B and 7, when the drilling tool 11 rotates in the reverse direction R2 during the diameter expansion stroke, the shutter device 30 closes. More specifically, when the drilling tool 11 rotates in the reverse direction R2, the opening / closing member 40 receives resistance from objects such as excavated material in the hole 5 via the resistance part 44, and rotates relative to the closing member 31 in the forward direction R1, causing the shutter device 30 to close. In the closed state, the opening / closing member 40 is positioned at a second predetermined rotational position in which the shutter device 30 is closed, by the other end 45b of the groove 45 contacting the rotation restricting member 34 (see Figure 3) in the circumferential direction. Alternatively, the opening / closing member 40 may be positioned at the second predetermined rotational position by the resistance portion 44 contacting the other end face 32c of the closing piece 32.

[0042] Since the resistance section 44 protrudes upward relative to the closing section 42, it can efficiently receive the resistance of objects such as excavated material. Therefore, the shutter device 30 can be switched to the closed state by utilizing the resistance of the excavated material.

[0043] Figure 8 is a cross-sectional view showing the injection process in which the fluid F is injected into the hole 5. Figure 9 is a cross-sectional view showing the state in which the ground G has been compacted by the injection process. In the press-in process, the fluid F is pressurized to the boring rod 12 by the above-mentioned pumping device, and the fluid F passes through the inside of the drilling tool 11 and is discharged into the hole 5 from the discharge port at the lower end of the drilling teeth 16. Here, the fluid F is a material with low fluidity, such as slag mortar. The fluid F is a hardening material and, after being press-injected into the hole 5, solidifies through a chemical reaction, forming a pile body within the hole 5.

[0044] During the press-in process, the fluid F is pressed into the hole 5 by the above-mentioned pumping device, and at the same time, the drilling machine 1 rotates the drilling tool 11 in the reverse direction R2. For this reason, during the press-in process, the shutter device 30 is in a closed state, similar to the diameter-expanding process shown in Figure 7.

[0045] During the injection process, the pressure from the injected fluid F is transmitted to the ground G, causing the ground G surrounding the hole 5 to be compacted.

[0046] During the press-fitting process, a portion of the fluid F injected into the hole 5 from the drilling teeth 16 rises above the bit 13 and reaches the leak suppression device 10. The fluid F that reaches the leak suppression device 10 is retained by the action of the leak suppression device 10 and becomes a packer body 50 that suppresses the leakage of fluid F from the hole 5.

[0047] Referring to Figures 2, 8, and 9, the rising fluid F moves above the fluid retention device 20 through the space between the outer surface of the fluid retention device 20 and the inner surface of the hole 5, and through the internal space 20a of the fluid retention device 20. In detail, the fluid F flows into the internal space 20a from the inlet opening 25 of the case peripheral wall 22. The fluid F that has flowed into the internal space 20a is discharged from the outlet opening 26 and flows upwards to the fluid retention device 20. In this way, the fluid F flows into the internal space 20a from the inlet opening 25 and is discharged from the internal space 20a through the outlet opening 26, thus accumulating within the fluid retention device 20 and becoming difficult to move upward. Since the fluid F has lower fluidity than the drilling water and excavated material generated during drilling, it tends to accumulate in the internal space 20a. For this reason, the packer body 50 can be effectively formed by providing the fluid retention device 20.

[0048] Since the fluid F flows into the internal space 20a from the inlet opening 25 facing the inner circumferential surface of the hole 5, it becomes more difficult for the fluid F to flow into the internal space 20a compared to, for example, the case where the inlet opening is provided in the lower wall portion 23 of the case. For this reason, the fluid retention device 20 can effectively retain the fluid F. Furthermore, since the sum of the areas of the outlet openings 26 is smaller than the sum of the areas of the inlet openings 25, the fluid F can be effectively retained in the internal space 20a.

[0049] Furthermore, the fluid F that moves upward from the fluid retention device 20 reaches the shutter device 30 and is retained by the shutter device 30. In detail, during the press-fitting process, the shutter device 30 is in a closed state, and the shutter opening 33 is blocked by the closing part 42, so the fluid F cannot pass through the shutter opening 33 and through the shutter device 30. As a result, the fluid F accumulates below the shutter device 30. Furthermore, a portion of the fluid F moves upward towards the shutter device 30 by passing between the outer surface of the shutter device 30 and the inner surface of the hole 5.

[0050] Thus, in the leak suppression device 10, a packer body 50 in which the fluid F is retained is formed above the bit 13 by the fluid retention device 20 and the shutter device 30. The packer body 50 acts as a lid to seal the top of the hole 5, preventing leakage of the fluid F from the hole 5. This prevents a decrease in the pressure during the injection of the fluid F, allowing the fluid F to be properly injected and the ground G to be effectively compacted.

[0051] After the press-in process is completed, the drilling tool 11 rises, the drilling tool 11 and the packer body 50 are removed from the hole 5, and a pile body formed from the hardened fluid F is created inside the hole 5.

[0052] As described above, according to an embodiment to which the present invention is applied, the leak suppression device 10 is provided on a drilling machine 1 that drills a hole 5 in the ground G using a drilling tool 11 comprising a boring rod 12 and a bit 13 provided at the lower end of the boring rod 12, and presses a fluid F into the hole 5 from the lower end of the drilling tool 11. The leak suppression device 10 is provided with a fluid retention device 20 on the outer circumference of the boring rod 12 above the bit 13. The fluid retention device 20 comprises a case 21 that surrounds the boring rod 12 and forms an internal space 20a between itself and the boring rod 12, an inlet opening 25 provided in the case 21 that connects the internal space 20a to the outside of the case 21, and an outlet opening 26 provided in the case 21 above the inlet opening 25 that connects the internal space 20a to the outside of the case 21. In this configuration, the fluid F that is pressed into the hole 5 in the ground G from the lower end of the drilling tool 11 and rises flows into the internal space 20a of the case 21 of the fluid retention device 20 through the inlet opening 25, and remains above the bit 13. As a result, the rise of the fluid F can be suppressed by the fluid retention device 20, preventing leakage of the fluid F and enabling effective compaction of the ground G. In addition, objects such as drilling water W and excavated material generated during drilling flow more easily than the fluid F, enter the internal space 20a through the inlet opening 25, and are discharged upward through the outlet opening 26. Therefore, objects in the hole 5 can be effectively discharged during drilling, and when the fluid F is pressed into the ground G, leakage of the fluid F pressed into the ground G is suppressed, enabling effective compaction of the ground G.

[0053] Furthermore, the case 21 includes a case peripheral wall portion 22 that surrounds the boring rod 12 from all sides, a case lower wall portion 23 that extends from the lower end of the case peripheral wall portion 22 toward the outer circumference of the boring rod 12, and a case upper wall portion 24 that extends from the upper end of the case peripheral wall portion 22 toward the outer circumference of the boring rod 12, with the inlet opening 25 provided in the case peripheral wall portion 22. With this configuration, since the inlet opening 25 is provided in the case peripheral wall portion 22, the inflow of the fluid F into the internal space 20a can be moderately suppressed, and the fluid F can be effectively retained. Furthermore, the case 21 comprises the case peripheral wall portion 22, the case lower wall portion 23, and the case upper wall portion 24, which restrict the flow of the fluid F in the internal space 20a in the downward, upward, and radial directions, thereby effectively retaining the fluid F.

[0054] Furthermore, the area of ​​the outlet opening 26 is smaller than the area of ​​the inlet opening 25. This configuration allows the fluid F to be effectively retained in the internal space 20a of case 21, thereby suppressing leakage of the fluid F.

[0055] Furthermore, the leak suppression device 10 is installed in a drilling machine 1 that drills a hole 5 in the ground G using a drilling tool 11 comprising a boring rod 12 and a bit 13 provided at the lower end of the boring rod 12, and presses a fluid F into the hole 5 from the lower end of the drilling tool 11. The leak suppression device 10 is equipped with a shutter device 30 on the outer circumference of the boring rod 12 above the bit 13. The shutter device 30 comprises a closing member 31 that extends radially outward from the outer circumference of the boring rod 12 and closes the hole 5, a shutter opening 33 that penetrates the closing member 31 in the axial direction of the boring rod 12, and an opening / closing member 40 that can open and close the shutter opening 33. With this configuration, when the shutter opening 33 is closed by the opening / closing member 40, the shutter device 30 can block the hole 5 and suppress the rise of the fluid F, thereby suppressing leakage of the fluid F. This makes it possible to effectively compact the ground G with the fluid F. Furthermore, when the shutter opening 33 is open by the opening / closing member 40, the shutter device 30 can allow objects in the hole 5, such as drilling water W, to pass through. This makes drilling easier.

[0056] Furthermore, the closing member 31 rotates integrally with the boring rod 12, and the opening / closing member 40 is provided so as to be rotatable relative to the closing member 31. The opening / closing member 40 rotates due to the resistance force it receives from the object in the hole 5 when the boring rod 12 rotates, thereby opening and closing the shutter opening 33. With this configuration, the shutter opening 33 can be opened and closed by rotating the opening / closing member 40 using the resistance force received from the object in the hole 5 when the boring rod 12 rotates, thus making it easy to open and close the shutter opening 33.

[0057] Furthermore, the opening / closing member 40 opens the shutter opening 33 when the boring rod 12 rotates in the forward rotation direction R1 to drill the hole 5, and closes the shutter opening 33 when the boring rod 12 rotates in the reverse rotation direction R2. With this configuration, the shutter opening 33 opens when the boring rod 12 rotates forward to drill the hole 5, allowing objects inside the hole 5, such as drilling water, to be discharged to the outside through the shutter opening 33 during drilling, thus enabling efficient drilling. Furthermore, the shutter opening 33 can be closed by rotating the boring rod 12 in the reverse direction, making it easy to close the shutter opening 33.

[0058] Furthermore, the opening / closing member 40 includes a closing portion 42 that overlaps with the shutter opening 33 and closes the shutter opening 33, and a resistance portion 44 that protrudes in the axial direction of the boring rod 12 relative to the closing portion 42. With this configuration, the resistance force from the object in the hole 5 can be efficiently received by the resistance portion 44 that protrudes in the axial direction of the boring rod 12. As a result, the opening / closing member 40 can be rotated by the resistance force, allowing the shutter opening 33 to be easily opened and closed.

[0059] Furthermore, the leak suppression device 10 includes both a fluid retention device 20 and a shutter device 30, with the shutter device 30 positioned above the fluid retention device 20. With this configuration, the flow of the fluid F, which is retained by the fluid retention device 20, is further blocked by the shutter device 30, thereby effectively suppressing leakage of the fluid F. As a result, the ground G can be effectively compacted by the injected fluid F.

[0060] [Differentiation] Figure 10 is a conceptual diagram showing a modified example of the above embodiment. In the above embodiment, the opening / closing member 40 was described as being positioned below the closing member 31, but it is also possible to configure it so that the opening / closing member 240 is positioned above the closing member 231, as in the shutter device 230 shown in Figure 10.

[0061] As shown in the upper part of Figure 10, when the shutter device 230 is open, the opening 243 of the opening / closing member 240 is in communication with the shutter opening 233 of the closing member 231, and drilling water and the like can pass through the shutter opening 233 and the opening 243 to pass through the shutter device 230.

[0062] As shown in the lower part of Figure 10, when the opening / closing member 240 rotates relative to the closing member 231 from an open state, the shutter device 230 enters a closed state. When the shutter device 230 is closed, the closing portion 242 of the opening / closing member 240 blocks the shutter opening 233 of the closing member 231 from above. As a result, the fluid F (Figure 8) cannot pass through the shutter opening 233 and remains below the shutter device 230.

[0063] Although one embodiment of the present invention has been described above, the present invention is not limited to such specific embodiments, and unless otherwise specifically limited in the above description, various modifications and changes are possible within the scope of the spirit of the present invention as described in the claims. For example, the configurations of the embodiments described above can be added or deleted as appropriate, and the configuration of one embodiment can be provided in other embodiments. Furthermore, the effects in the embodiments described above are merely illustrative of the effects that may arise from the present invention, and do not mean that the effects of the present invention are limited to the effects described above. In the above embodiment, the leak suppression device 10 was described as comprising both the fluid retention device 20 and the shutter device 30, but the present invention is not limited thereto. The leak suppression device 10 only needs to include at least one of the fluid retention device 20 and the shutter device 30. [Explanation of Symbols]

[0064] 1: Drilling machine 5: Hole 10: Leak suppression device 11: Drilling Tools 12: Bowling rod (rod) 13:bit 20:Fluid retention device 20a: Internal space 21: Case 22: Case peripheral wall 23: Lower wall of the case 24: Upper wall of the case 25: Entrance opening 26:Exit opening 30,230: Shutter device 31,231: Closure member 33,233: Shutter opening 40,240: Opening / closing member 42,242: Occlusion 44:Resistance part F:Fluid

Claims

1. A leak suppression device provided in a drilling machine that drills a hole in the ground using a drilling tool comprising a rod and a bit provided at the lower end of the rod, and presses a fluid into the hole from the lower end of the drilling tool, A fluid retention device is provided on the outer circumference of the rod above the bit, The fluid retention device comprises a case surrounding the rod and forming an internal space between the rod and the case, an inlet opening provided in the case that connects the internal space to the outside of the case, and an outlet opening provided above the inlet opening in the case that connects the internal space to the outside of the case.

2. The case comprises a case peripheral wall portion that surrounds the rod from the outside, a case lower wall portion that extends from the lower end of the case peripheral wall portion toward the outer circumference of the rod, and a case upper wall portion that extends from the upper end of the case peripheral wall portion toward the outer circumference of the rod. The leak suppression device according to claim 1, wherein the inlet opening is provided in the peripheral wall of the case.

3. The leak suppression device according to claim 1, wherein the area of ​​the outlet opening is smaller than the area of ​​the inlet opening.

4. A leak suppression device provided in a drilling machine that drills a hole in the ground using a drilling tool comprising a rod and a bit provided at the lower end of the rod, and presses a fluid into the hole from the lower end of the drilling tool, A shutter device is provided on the outer circumference of the rod above the bit, The shutter device is a leak suppression device comprising a closing member extending radially outward from the outer circumference of the rod and closing the hole, a shutter opening through the closing member in the axial direction of the rod, and an opening / closing member capable of opening and closing the shutter opening.

5. The closing member rotates integrally with the rod, and the opening / closing member is provided so as to be rotatable relative to the closing member. The leak suppression device according to claim 4, wherein the opening / closing member rotates due to the resistance force received from an object in the hole when the rod rotates, thereby opening and closing the shutter opening.

6. The leak suppression device according to claim 5, wherein the opening and closing member opens the shutter opening when the rod rotates in the forward direction to drill the hole, and closes the shutter opening when the rod rotates in the reverse direction.

7. The leak suppression device according to claim 5, wherein the opening and closing member comprises a closing portion that overlaps with the shutter opening and closes the shutter opening, and a resistance portion that protrudes in the axial direction of the rod relative to the closing portion.

8. The system comprises both the fluid retention device of claim 1 and the shutter device of claim 4, The shutter device is a leak suppression device positioned above the fluid retention device.

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