Material discharge system and material discharge method

Abstract

To efficiently backfill an excavated hole.SOLUTION: The material release system 100 includes the outer tube 10 extending along the borehole 2, the conveying unit 16 movable in the outer tube 10 and restricted in downward movement by the outer tube 10 at a predetermined depth, and the working fluid supply device 18 capable of supplying the working fluid to the conveying unit 16. The conveyance unit 16 includes the inner tube 20, the piston 46 provided in the inner tube 20, the accommodation chamber S defined in the inner tube 20 on the lower side of the piston 46 and in which the material 5 is accommodated, and the pressure chamber 28 defined in the inner tube 20 on the side opposite to the accommodation chamber S across the piston 46 and to which the working fluid is guided, and the material in the accommodation chamber S is pushed out into the borehole 2 by the piston 46 moving downward by the pressure of the working fluid in the pressure chamber 28.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a material delivery system and a material delivery method. [Background technology]

[0002] Patent Document 1 discloses a material discharging device that discharges material into a borehole. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 8-36098 Summary of the Invention [Problem to be solved by the invention]

[0004] Generally, boreholes excavated during boring surveys to confirm geological structures, etc., are backfilled with materials such as filler after the survey is completed. Backfilling of a borehole is performed, for example, as described in Patent Document 1, by transporting a container containing material to a predetermined depth within the borehole and then opening the container's discharge port to release the material. Backfilling a borehole requires the container to be raised and lowered multiple times within the borehole. However, in boreholes with easily collapsing walls, there is a risk that the container cannot be lowered to the predetermined depth due to collapsed soil or that the container becomes buried in the collapsed soil, making it impossible to retrieve, thereby reducing the efficiency of the borehole backfilling work.

[0005] The present invention aims to efficiently backfill a borehole. [Means for solving the problem]

[0006] The present invention provides a material discharge system for discharging material into a borehole, comprising a cylindrical outer tube extending along the borehole, a transport unit movable within the outer tube and whose downward movement is restricted by the outer tube at a predetermined depth, and a working fluid supply device capable of supplying a working fluid to the transport unit, wherein the transport unit has a cylindrical inner tube movable within the outer tube, a piston provided within the inner tube, a storage chamber defined within the inner tube below the piston and in which the material is stored, and a pressure chamber defined within the inner tube on the opposite side of the piston to the storage chamber and into which the working fluid is guided, and the material in the storage chamber is pushed into the borehole when the piston moves downward due to the pressure of the working fluid in the pressure chamber.

[0007] The present invention also provides a material discharging method for discharging material into a borehole, comprising: an adjustment step of adjusting the lower end position of a cylindrical outer tube extending along the borehole according to the depth to which the material is to be discharged; a movement step of inserting a transport unit into the outer tube and moving it downward until its downward movement is restricted by the outer tube, the transport unit having a cylindrical inner tube movable within the outer tube, a piston provided within the inner tube, a storage chamber defined within the inner tube below the piston and for storing the material, and a pressure chamber defined within the inner tube on the opposite side of the piston from the storage chamber and for directing a working fluid; a supply step of supplying the working fluid to the transport unit; and an extrusion step of extruding the material in the storage chamber into the borehole by moving the piston downward using the pressure of the working fluid in the pressure chamber. [Effects of the Invention]

[0008] According to the present invention, the borehole can be backfilled efficiently. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic diagram showing the overall configuration of a material release system according to an embodiment of the present invention. [Figure 2] 1 is a cross-sectional view of an outer tube of a material delivery system according to an embodiment of the present invention. [Figure 3] 1 is a cross-sectional view of a transport unit of a material discharging system according to an embodiment of the present invention. [Figure 4] FIG. 4 is an enlarged view of a cross section taken along line AA in FIG. 3. [Figure 5] FIG. 4 is an enlarged view of a cross section taken along line BB in FIG. 3. [Figure 6] FIG. 4 is an enlarged view of a cross section taken along line CC in FIG. [Figure 7] 1A-1C are diagrams illustrating a material release method according to an embodiment of the present invention in chronological order. [Figure 8] 10A and 10B are diagrams for explaining the process of breaking a fragile member, showing the state of the fragile member before breaking. [Figure 9] 10A and 10B are diagrams for explaining the process of breaking a fragile member, and are diagrams showing the state after the fragile member has broken. [Figure 10] 8A to 8C are diagrams showing a material releasing method according to an embodiment of the present invention in chronological order, showing a state following FIG. 7. [Figure 11] 10A to 10C are diagrams showing a material release method according to an embodiment of the present invention in chronological order, and are diagrams showing states following FIG. [Figure 12] 12A to 12C are diagrams showing a material release method according to an embodiment of the present invention in chronological order, showing states following FIG. 11. [Figure 13] 10A and 10B are diagrams illustrating modified examples of the transport unit of the material discharge system according to the embodiment of the present invention. [Figure 14] 10A and 10B are diagrams illustrating another modified example of the transport unit of the material discharging system according to the embodiment of the present invention. [Figure 15] FIG. 15 is an enlarged view of a cross section taken along line DD in FIG. [Figure 16] 10 is a diagram showing a state in which the movement restriction is released in another modified example of the transport unit. FIG. [Figure 17] FIG. 1 is a diagram showing a reference example of a material discharging system. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, a material discharging system and a material discharging method according to an embodiment of the present invention will be described with reference to the drawings.

[0011] First, the overall configuration of a material release system 100 according to an embodiment of the present invention will be described with reference to Figures 1 to 6. The material release system 100 is a so-called dump bailer system that transports and releases filler material such as bentonite into a borehole 2 drilled in the ground 1, for example, a borehole drilled to confirm the geological structure, etc., in order to backfill the borehole 2. The borehole 2 drilled for geological surveys may be several hundred meters deep and have an inner diameter as small as about 20 cm, but the borehole 2 to which the material release system 100 is applied is not limited to this.

[0012] As shown in Figure 1, the material release system 100 comprises a cylindrical outer tube 10 extending along the borehole 2, a conveying unit 16 that is movable within the outer tube 10 and transports and releases a material 5 such as bentonite downward into the borehole 2, and a working fluid supply device 18 that supplies a working fluid such as pressurized water into the outer tube 10 to supply the working fluid to the conveying unit 16.

[0013] The conveying unit 16 has a cylindrical inner tube 20 formed so as to be movable within the outer tube 10, a columnar piston 46 provided within the inner tube 20, a storage chamber S defined within the inner tube 20 below the piston 46 and containing a material 5 such as bentonite, and a pressure chamber 28 defined within the inner tube 20 on the opposite side of the piston 46 from the storage chamber S and into which a working fluid is introduced. The conveying unit 16 shown in Fig. 1 also has a housing 40 provided so as to be movable within the inner tube 20, and the piston 46 is fixed to the housing 40 via a frangible pin 55 described below.

[0014] As shown in FIG. 2, the outer tube 10 is a hollow tubular member and is composed of a plurality of extension tubes 11 connected to each other by screwing or the like, and a regulating tube 12 attached to the lowest end of the extension tubes 11.

[0015] The regulating tube 12 restricts the downward movement of the transport unit 16 at a predetermined depth, and its inner circumferential surface is formed with a restricting step 13 that restricts the downward movement of the transport unit 16 when a switching member 30 (described later) provided on the inner tube 20 abuts against it, as shown in FIG. 2 , and a locking groove 14 that locks with a latch portion 63 (described later) of the transport unit 16. On the other hand, the inner circumferential surface of the extension tube 11 is smooth and without any irregularities. The restricting step 13 is a step formed by making the inner diameter of the regulating tube 12 on the lower side smaller than the inner diameter of the regulating tube 12 on the upper side, and functions as a movement restricting portion that restricts the downward movement of the transport unit 16, and also functions as a position switching portion that switches the position of the switching member 30, as described later.

[0016] The position of the lower end of the regulating pipe 12 in the borehole 2 can be adjusted by changing the number of extension pipes 11 connected and the length of extension pipes 11 protruding from the ground surface. By changing the position of the lower end of the regulating pipe 12 in this way and changing the position of the limiting step 13 that limits the movement of the transport unit 16, the depth to which the material 5 is released from the transport unit 16 can be changed.

[0017] Next, the specific configuration of the conveying unit 16 will be described with reference to Figures 3 to 6. In the following description, the lower side of the conveying unit 16, which is the lower side when inserted into the outer tube 10 as shown in Figure 3, will be referred to as "bottom", "lower", or "lower side", and the opposite side will be referred to as "top", "upper", or "upper side".

[0018] The inner tube 20 is a cylindrical member having a plurality of cylindrical portions. As shown in Fig. 3, the inner tube 20 has a first cylindrical portion (inner tube first cylindrical portion) 21, a second cylindrical portion (inner tube second cylindrical portion) 22 located above the first cylindrical portion 21, and a third cylindrical portion (inner tube third cylindrical portion) located further above the second cylindrical portion 22.

[0019] The inner diameter of the first cylindrical portion 21 is larger than the inner diameter of the second cylindrical portion 22, the inner diameter of the second cylindrical portion 22 is larger than the inner diameter of the third cylindrical portion 23, and the inner diameter of the first cylindrical portion 21 is larger than the inner diameter of the third cylindrical portion 23. In addition, the outer diameter of the first cylindrical portion 21 is larger than the outer diameter of the second cylindrical portion 22, the outer diameter of the second cylindrical portion 22 is larger than the outer diameter of the third cylindrical portion 23, and the outer diameter of the first cylindrical portion 21 is larger than the outer diameter of the third cylindrical portion 23.

[0020] The first cylindrical portion 21 holds the housing 40 on its inner circumferential surface 21a so that it can slide vertically, and holds the piston 46 so that it can move vertically via the housing 40. In addition, the third cylindrical portion 23 is formed into a shape that can hold a fragile member 50, which will be described later.

[0021] Within the inner tube 20, a pressure chamber 28 into which a working fluid such as pressurized water is introduced is formed in an area surrounded by the second tubular portion 22, the third tubular portion 23, the housing 40, and a lid portion 61 (described later), and the upper surface 40a of the housing 40 faces the pressure chamber 28. Therefore, when the pressure of the working fluid within the pressure chamber 28 acts on the upper surface 40a of the housing 40, a load is generated that pushes the housing 40 downward, and when the fragile member 50 breaks as described below, the housing 40 moves downward along the first tubular portion 21 due to this load.

[0022] An opening / closing door 25 that opens and closes the lower opening is attached below the inner tube 20 so as to be rotatable around a support pin 26. The end of the opening / closing door 25 opposite the end where the support pin 26 is provided is fixed to the first tubular portion 21 via a frangible pin 57, which will be described later, and the lower opening of the inner tube 20 is closed.

[0023] The inner surface 21a of the first cylindrical portion 21 is a sliding surface against which the outer surface of the housing 40 slides, and a lower step 21b (limiting portion) is provided at the lower end of the inner surface 21a to limit the downward movement of the housing 40, and an upper step 21c is provided at the upper end of the inner surface 21a to limit the upward movement of the housing 40.

[0024] The position of the lower step 21b is set so that, in order to push open the opening and closing door 25 with the housing 40, the housing 40 stops at the lower step 21b and protrudes a predetermined length from below the inner tube 20. The position at which the upper step 21c is provided is not limited to the position shown in Fig. 3, and may be provided, for example, near the middle of the first tubular portion 21 in the up-down direction.

[0025] The inner circumferential surface 23a of the third tubular portion 23 forms an insertion hole into which the fragile member 50 is inserted, and a lid portion 61 of the head portion 60, which will be described later, is attached to the outer circumferential surface of the third tubular portion 23. The lid portion 61 functions as a lid member that seals the inner circumferential surface 23a of the third tubular portion 23, into which the fragile member 50 is inserted, from the outside, and prevents the working fluid supplied into the outer tube 10 from flowing into the inner tube 20 through an opening that opens in the upper end surface of the third tubular portion 23.

[0026] 4, a plurality of passages 29 penetrating radially are formed in the second cylindrical portion 22, and a cylindrical switching member 30 capable of closing the passages 29 is provided on the outer periphery of the second cylindrical portion 22. A plurality of through holes 31 penetrating radially are formed on the lower side of the switching member 30 at positions connected to the passages 29 formed in the second cylindrical portion 22 when viewed in the axial direction (see FIG. 4).

[0027] In addition, a crescent-shaped or rod-shaped key member 32 is arranged between the second tubular portion 22 and the switching member 30 to restrict rotation of the switching member 30 relative to the second tubular portion 22, and an accommodation groove is formed on the outer peripheral surface of the second tubular portion 22 to accommodate the key member 32, while a sliding groove is formed on the inner peripheral surface of the switching member 30 along the axial direction to allow the key member 32 to slide.

[0028] 3, when the second tubular portion 22 moves downward relative to the switching member 30 from the state shown in Fig. 3 due to the lower end of the switching member 30 abutting against the limiting step 13 of the outer tube 10, the passage 29 and the through-hole 31 are communicated with each other, and the pressure chamber 28 formed inside the second tubular portion 22 is communicated with the outside through the passage 29 and the through-hole 31, i.e., a state is achieved in which working fluid such as pressurized water can be supplied from the outside into the pressure chamber 28. Specifically, as shown in Fig. 8 described later, the working fluid supplied into the outer tube 10 is supplied to the pressure chamber 28 through a gap formed between the inner circumferential surface of the outer tube 10 and the outer circumferential surface of the third tubular portion 23 and / or the cover portion 61, a gap formed between the inner circumferential surface of the outer tube 10 and the switching member 30, the through-hole 31, and the passage 29.

[0029] To summarize the relationship between the passage 29 and the through hole 31 of the switching member 30, the passage 29 formed in the inner tube 20 of the conveying unit 16 is a passage that connects the inside of the inner tube 20 (the pressure chamber 28 side) and the outside of the inner tube 20 (the inside of the outer tube 10 and the outside of the inner tube 20), and is a flow path through which the working fluid flows.The switching member 30 can block the flow of the working fluid flowing in the passage 29 by blocking the passage 29, and can allow the flow of the working fluid flowing in the passage 29 by connecting the passage 29 to the through hole 31 and opening the passage 29.

[0030] Furthermore, as long as the through hole 31 of the switching member 30 functions as a passage that connects the inside and outside of the inner tube 20 by communicating with the passage 29, it does not have to be a hole that penetrates radially, but may be a notch formed along the radial direction, or a recess or V-shaped groove that opens at the upper end surface and inner surface of the switching member 30.

[0031] In addition, the position of the switching member 30 is switched from a blocking position that blocks the passage 29 to an opening position that opens the passage 29 when the lower end of the switching member 30 abuts against the restricting step 13 of the outer tube 10. By switching the position of the switching member 30 in this manner, the passage 29 is connected to the through hole 31 and is in an open state, so the restricting step 13 functions as a position switching section that switches the position of the switching member 30.

[0032] Additionally, O-rings 34 and 35 are disposed on the outer peripheral surface of the second cylindrical portion 22, one above the other and one below the other, with the passage 29 sandwiched between them. Therefore, as shown in Fig. 3, in a closed state in which the passage 29 is closed by the switching member 30, the O-rings 34 and 35 prevent working fluid such as pressurized water and liquid such as groundwater from entering the passage 29 through the gap between the outer peripheral surface of the second cylindrical portion 22 and the inner peripheral surface of the switching member 30. In other words, the pressure in the pressure chamber 28 is maintained at a constant, relatively low pressure until the working fluid is supplied from the working fluid supply device 18 through the passage 29, as will be described later.

[0033] Furthermore, a lower step 22a that limits downward movement of the switching member 30 is provided at the lower end of the outer peripheral surface of the second cylindrical portion 22, and an upper step 22b that limits upward movement of the switching member 30 is provided at the upper end of the outer peripheral surface of the second cylindrical portion 22. Note that in the example shown in Fig. 3, the lid portion 61 attached to the third cylindrical portion 23 constitutes the upper step 22b, but the upper step 22b may be a plurality of protrusions formed to protrude from the outer peripheral surface of the second cylindrical portion 22, or the upper step 22b may be a step portion formed by making the outer diameter of the inner tube 20 on the upper side larger than the outer diameter of the inner tube 20 on the lower side.

[0034] The position where the lower step 22a is formed is set so that the passage 29 is sealed by the switching member 30 and the O-rings 34, 35 when the switching member 30 abuts against the lower step 22a, and the position where the upper step 22b is formed is set so that the passage 29 and the through hole 31 are connected when the switching member 30 abuts against the upper step 22b.

[0035] An O-ring 33 that is compressed by the inner tube 20 and the outer tube 10 is disposed on the outer peripheral surface of the second cylindrical portion 22 below the lower step 22a. By providing the O-ring 33 below the passage 29 in this manner, groundwater or the like is prevented from flowing into the gap between the inner peripheral surface of the outer tube 10 and the outer peripheral surface of the switching member 30 or the gap between the inner peripheral surface of the outer tube 10 and the outer peripheral surface of the second cylindrical portion 22 through the gap between the inner peripheral surface of the outer tube 10 and the outer peripheral surface of the switching member 30 or the gap between the inner peripheral surface of the outer tube 10 and the outer peripheral surface of the second cylindrical portion 22, and working fluid such as pressurized water is prevented from flowing into the gap between the inner peripheral surface of the outer tube 10 and the outer peripheral surface of the first cylindrical portion 21 through the gap between the inner peripheral surface of the outer tube 10 and the outer peripheral surface of the switching member 30 or the gap between the inner peripheral surface of the outer tube 10 and the outer peripheral surface of the second cylindrical portion 22.

[0036] This prevents the working fluid, such as pressurized water, supplied from above from flowing out downward, and as a result, the working fluid can efficiently flow into the pressure chamber 28. Furthermore, the O-ring 33 is provided below the lower step 22a, and even if the switching member 30 moves downward, it abuts against the lower step 22a to limit its movement, so the O-ring 33 will not be damaged by the switching member 30. The O-ring 33 may also be disposed on the outer circumferential surface of the first cylindrical portion 21.

[0037] In this way, the inner tube 20 is provided with a passage 29 that can guide the working fluid, such as pressurized water, supplied from the working fluid supply device 18 to the pressure chamber 28, and the conveying unit 16 has a switching member 30 that can switch this passage 29 from a closed state to an open state.

[0038] The housing 40 is a cylindrical member having a first cylindrical portion (housing first cylindrical portion) 41 that holds the piston 46 so that it can slide up and down, and a second cylindrical portion 42 (housing second cylindrical portion) that supports a rod 47 that extends upward from the piston 46. Within the housing 40, an accommodation chamber S is defined by an inner circumferential surface 41a of the first cylindrical portion 41 and a lower end surface 46a of the piston 46, and accommodates a material 5 such as pelletized bentonite. In this way, the accommodation chamber S and the pressure chamber 28 are defined within the inner tube 20, with the piston 46 sandwiched between them.

[0039] The inner circumferential surface 41a of the first cylindrical portion 41 serves as a sliding surface against which the outer circumferential surface of the piston 46 slides, and a lower step 41b is provided at the lower end of the inner circumferential surface 41a. The lower step 41b abuts against the lower end surface 46a of the piston 46, thereby limiting the downward movement of the piston 46. On the other hand, the upward movement of the piston 46 is limited by the abutment of the upper end surface 46b of the piston 46 against a step 43 formed between the inner circumferential surface 41a of the first cylindrical portion 41 and the inner circumferential surface 42a of the second cylindrical portion 42. In other words, the piston 46 is accommodated in the housing 40 with the annular upper end surface 46b formed on its upper surface facing and abutting against the step 43 of the housing 40.

[0040] The lower step 41b is not annular, but has a discontinuous shape in the circumferential direction as shown in Fig. 5. Specifically, the lower step 41b is formed, for example, by cutting out a step portion that is initially formed into an annular shape in multiple locations along the inner circumferential surface 41a in the axial direction. By not making the lower step 41b that protrudes radially inward into an annular shape in this way, it is possible to prevent the lower step 41b from interfering with the movement of the material 5 when the material 5 contained in the storage chamber S is pushed out by the piston 46, as described below.

[0041] Furthermore, a step 41c is formed on the outer peripheral surface of the first cylindrical portion 41, which can come into contact with a lower step 21b formed on the inner tube 20 in order to restrict downward movement of the housing 40. In other words, downward movement of the housing 40 relative to the inner tube 20 is restricted by the step 41c coming into contact with the lower step 21b. It is preferable that the outer peripheral surface of the first cylindrical portion 41 above the step 41c be formed to have the same diameter as the outer peripheral surface of the second cylindrical portion 42.

[0042] Furthermore, a pressing portion 44 that presses the opening / closing door 25 is provided at the lower end of the first cylindrical portion 41. The pressing portion 44 is the portion that first comes into contact with the opening / closing door 25 when the housing 40 moves downward inside the inner tube 20.

[0043] 6, the opening / closing door 25 is fixed to the first cylindrical portion 21 via a frangible pin 57 that is provided so as to penetrate the opening / closing door 25 and the first cylindrical portion 21 of the inner tube 20. In other words, when the frangible pin 57 is broken, the opening / closing door 25 rotates about the support pin 26, opening the lower opening of the inner tube 20, i.e., enabling the material 5 contained in the storage chamber S to be released.

[0044] In other words, the pressing portion 44 is provided to generate a load between the first tubular portion 21 and the opening / closing door 25 that will break the frangible pin 57. For this reason, the pressing portion 44 is shaped so that it comes into contact with a portion of the opening / closing door 25 that is closer to the frangible pin 57 and can apply a concentrated load to this portion. Specifically, as shown in FIG. 3, the lower edge of the first tubular portion 41 is formed with an inclination so as to protrude downward as it approaches the frangible pin 57, and the portion that protrudes most downward forms the pressing portion 44.

[0045] The piston assembly 45 is a stepped rod-shaped member in which a piston 46 and a rod 47 extending upward from the piston 46 are integrated, and the rod 47 is fixed to the second cylindrical portion 42 via a frangible pin 55, thereby being fixed to the housing 40. In other words, if the frangible pin 55 breaks, the piston 46 can move up and down within the housing 40.

[0046] Furthermore, a fragile member 50 is attached to the upper end of the rod 47.

[0047] The fragile member 50 is a member made of a relatively low-strength material such as an aluminum alloy, and has a flange portion 51 having a diameter larger than the inner circumferential surface 23a of the third tubular portion 23, an insertion portion 52 inserted into the rod 47, and a constricted portion 53 provided between the flange portion 51 and the insertion portion 52. As shown in FIG. 3 , the fragile member 50 is installed so that the constricted portion 53 is housed within the third tubular portion 23, and the insertion amount of the insertion portion 52 into the rod 47 is set so that the housing 40 comes into contact with the upper step 21c of the inner tube 20.

[0048] The frangible member 50 is provided to fix the housing 40, which is integrated with the piston assembly 45, to the inner tube 20 via the frangible pin 55. In other words, if the frangible member 50 breaks at the constricted portion 53, the housing 40 and the piston assembly 45 can move within the inner tube 20.

[0049] The head portion 60, which is attached above the inner tube 20 via the lid portion 61, forms part of the transport unit 16 and has a pair of latch portions 63 and a spear head 65 used to lift the transport unit 16.

[0050] The pair of latch portions 63 are a pair of plate-like members attached via support pins 63a to extension portions 62 that extend upward from the lid portion 61, and are each rotatable about the support pins 63a. The upper ends of the pair of latch portions 63 are each biased radially outward by a spring (not shown).

[0051] The spear head 65 is fixed via a fixing pin 66 to the top of a cylindrical member 64 that surrounds the extension portion 62, and its upper end is shaped so that it can be connected to the lifting dock of the overshot assembly used when retrieving the transport unit 16.

[0052] The cylindrical member 64 is connected to the extending portion 62 so as to be movable in the vertical direction via a connecting pin 67 that is inserted into a long hole 62a formed in the extending portion 62 along the vertical direction. In addition, the cylindrical member 64 is formed with a pair of slits 64a that allow the pair of latch portions 63 to protrude radially outward.

[0053] Therefore, when the load pulling up the spear head 65 acts on the tubular member 64 via the spear head 65, the tubular member 64 is pulled upward together with the spear head 65, as shown in Figure 12 described below, and the lower ends of the pair of slits 64a come into contact with the pair of latch portions 63, causing the upper ends of the pair of latch portions 63 to move radially inward against the spring force.

[0054] In this way, the pair of latches 63 provided on the head portion 60 are configured to be able to be engaged with and released from the locking grooves 14 provided on the inner peripheral surface of the regulating tube 12. In other words, the latches 63 are members that can be freely moved in and out of the conveying unit 16 in the radial direction.

[0055] When the pair of latch portions 63 are locked in the locking grooves 14, the upward movement of the transport unit 16 is restricted, so that even if, for example, groundwater pressure acts on the underside of the transport unit 16 and generates a force pushing the transport unit 16 upward, the transport unit 16 is prevented from moving upward. In this way, the locking grooves 14 function as movement restricting portions that restrict the upward movement of the transport unit 16.

[0056] The downward movement of the transport unit 16 is restricted when the switching member 30 abuts against the limiting step 13 of the regulating tube 12, and the upward movement of the switching member 30 is restricted by the upper step 22b. In other words, the upper step 22b provided on the transport unit 16 engages with the limiting step 13 provided on the regulating tube 12 of the outer tube 10 via the switching member 30, thereby restricting the downward movement of the transport unit 16 to a predetermined depth. In this way, the limiting step 13 functions as a movement restricting section that restricts the downward movement of the transport unit 16.

[0057] In this embodiment, the limiting step 13 functions as a position switching part that switches the position of the switching member 30, and also functions as a movement limiting part that limits the downward movement of the transport unit 16. Alternatively, two different step parts may be provided in the regulating pipe 12 of the outer tube 10, with one step part functioning as a position switching part that switches the position of the switching member 30 and the other step part functioning as a movement limiting part that limits the downward movement of the transport unit 16.

[0058] Furthermore, the position switching portion and the movement restricting portion are not limited to portions formed in a step shape such as the restricting step 13, but may also be formed in a groove shape in the restricting tube 12 of the outer tube 10 as in the modified examples shown in Figures 14 to 16 described below.

[0059] On the other hand, when the pair of latch portions 63 are released from the locking groove 14, the transport unit 16 becomes capable of moving upward.

[0060] The working fluid supply device 18 that supplies working fluid to the transport unit 16 configured as described above is a pressure pump that pressurizes water, and supplies pressurized water as working fluid to the transport unit 16 through the outer tube 10. Note that the working fluid is not limited to pressurized water, and may be other pressurized fluids.

[0061] Next, a material discharging method performed using the material discharging system 100 having the above configuration will be described with reference to FIGS.

[0062] First, as shown in (a) of Figure 7, the outer tube 10 is inserted into the borehole 2 to a predetermined depth. Specifically, the position of the lower end of the outer tube 10, i.e., the position of the regulating pipe 12, is adjusted by pushing down or pulling up the outer tube 10 depending on the depth to which the material 5 is to be released (adjustment step). In addition, the extension pipe 11 may be added or removed as necessary.

[0063] If a collapse occurs in the borehole 2 and the outer tube 10 cannot be inserted to a predetermined depth, the collapsed earth and sand may be removed in advance, for example, by a known wireline construction method. In this case, the outer tube 10 may also be used as a drilling rod.

[0064] After the installation of the outer tube 10 is completed, as shown in FIG. 7(b), The transport unit 16, with the material 5 stored in the storage chamber S, is inserted into the outer tube 10 and moved downward (moving step). The transport unit 16 descends within the outer tube 10 due to its own weight, but if the water pressure of the groundwater prevents the downward movement, pressurized water may be supplied from the working fluid supply device 18, and the transport unit 16 may be moved downward by the pressure of the pressurized water.

[0065] While the conveying unit 16 is moving downward, the passage 29 is blocked by the switching member 30 and the gap between the outer peripheral surface of the second cylindrical portion 22 and the inner peripheral surface of the switching member 30 is sealed by the O-rings 34, 35, so that even if groundwater or the like has entered the outer tube 10, the groundwater or the like is prevented from entering the pressure chamber 28 through the passage 29. Furthermore, the repulsive forces (restoring forces) of the O-rings 34, 35 urge the switching member 30 radially outward, so that the position of the switching member 30 is prevented from switching from a position that blocks the passage 29 to a position that opens it while the conveying unit 16 is moving downward.

[0066] When the transport unit 16 reaches a predetermined depth, the downward movement of the transport unit 16 is restricted by the restricting pipe 12 provided at the lowest end of the outer tube 10, as shown in FIG. 7(c).

[0067] Specifically, after the switching member 30 abuts against the restricting step 13 of the regulating tube 12 and moves upward relative to the conveying unit 16 and the inner tube 20, further upward movement of the switching member 30 is restricted by the upper step 22b, thereby restricting the downward movement of the conveying unit 16.

[0068] At the same time, the pair of latch portions 63 are locked in the locking grooves 14 provided on the inner peripheral surface of the regulating pipe 12, thereby restricting the upward movement of the transport unit 16.

[0069] By restricting the downward and upward movement in this manner, the transport unit 16 is stopped at a predetermined position.

[0070] When it is confirmed that the transport unit 16 has reached a predetermined depth and stopped, pressurized water is supplied from the working fluid supply device 18 (supply process). Whether the transport unit 16 has reached a predetermined depth and stopped can be determined, for example, by detecting an impact sound generated when the switching member 30 abuts against the limiting step 13, an impact sound generated when the switching member 30 abuts against the upper step 22b, or an impact sound generated when the pair of latch portions 63 engage with the engagement grooves 14. Note that a beacon transmitter may be provided in the transport unit 16, and its position may be detected to determine whether the transport unit 16 has reached a predetermined depth.

[0071] When the switching member 30 abuts against the limiting step 13 of the outer tube 10 and moves upward relative to the inner tube 20, and then abuts against the upper step 22b, the conveying unit 16 stops within the outer tube 10, and as shown in Figure 8, the passage 29 and the through hole 31 are connected, that is, pressurized water (working fluid) can be supplied into the pressure chamber 28 through the passage 29 and the through hole 31.

[0072] In this state, the pressurized water supplied from the working fluid supply device 18 passes through the gap between the inner surface of the regulating pipe 12 and the outer surface of the switching member 30, passes through the through hole 31 and the passage 29, and reaches the pressure chamber 28, as shown by the arrows in Figure 8.

[0073] In this embodiment, almost simultaneously with the downward movement of the conveying unit 16 being restricted by the restricting step 13 provided in the outer tube 10, the through hole 31 of the switching member 30 and the passage 29 communicate with each other, and the passage 29 that guides the working fluid to the pressure chamber 28 is opened. In other words, the downward movement of the conveying unit 16 is restricted by the restricting step 13 that functions as a movement restrictor, and the passage 29 is opened when the position of the switching member 30 is switched from the closed position to the open position by the restricting step 13 that functions as a position switching part, and thus the working fluid is guided through the passage 29 to the pressure chamber 28.

[0074] However, for example, by providing a plug made of an elastic material such as rubber in the through hole 31 or in the passage 29, which is removed with a slight time lag after the pressure of the working fluid acts on the through hole 31, it is possible to provide a slight time lag between the restriction of the downward movement of the conveying unit 16 and the opening of the passage 29. In this way, the passage 29 can be opened almost simultaneously with the restriction of the downward movement of the conveying unit 16 by the outer tube 10, or with a slight time lag.

[0075] The pressurized water supplied into the pressure chamber 28 acts on the upper surface 40a (pressure-receiving surface) of the housing 40 facing the pressure chamber 28, generating a load that presses the housing 40 downward. This load that presses the housing 40 downward acts on the piston assembly 45 via the upper end surface 46b of the piston 46 that abuts against the stepped portion 43 of the housing 40, and as a result, the downward load caused by the pressure of the pressurized water in the pressure chamber 28 acts on the fragile member 50 via the rod 47 of the piston assembly 45.

[0076] When the load acting on fragile member 50 via rod 47, i.e., the load pulling insertion portion 52 of fragile member 50 downward, exceeds the breaking load of constricted portion 53, constricted portion 53 breaks, as shown in Fig. 9. When constricted portion 53 breaks, in addition to upper surface 40a of housing 40, the upper end surface of rod 47 facing pressure chamber 28 and the upper surface of the broken fragile member 50 become pressure-receiving surfaces that receive the pressure of the pressurized water in pressure chamber 28. The pressure acting on these pressure-receiving surfaces generates a load that moves housing 40 and piston assembly 45 downward, and housing 40 moves downward within inner tube 20 together with piston assembly 45.

[0077] The breaking load of the constricted portion 53 is set in advance based on the pressure of the pressurized water supplied from the working fluid supply device 18, the size of the pressure-receiving surface of the housing 40 facing the pressure chamber 28, the cross-sectional area of ​​the constricted portion 53, etc., so that the constricted portion 53 breaks when pressurized water of a predetermined pressure is supplied from the working fluid supply device 18.

[0078] 10, downward movement of the housing 40 is restricted by the step 41c of the housing 40 abutting against the lower step 21b of the inner tube 20. In other words, at the abutment portion between the step 41c of the housing 40 and the lower step 21b of the inner tube 20, a reaction force that resists the load corresponding to the pressure of the pressure chamber 28 acting on the upper surface 40a of the housing 40 is generated. As a result, the housing 40 comes to a stop relative to the inner tube 20.

[0079] Furthermore, before the step portion 41c abuts against the lower step 21b, the pressing portion 44 of the housing 40 abuts against the portion of the opening / closing door 25 near the frangible pin 57, causing the frangible pin 57 to break, and the opening / closing door 25 is pushed open by the housing 40 protruding from the lower end of the inner tube 20, as shown in Figure 10.

[0080] The breaking load of the frangible pin 57 is set in advance based on the pressure of the pressurized water supplied from the working fluid supply device 18, the size of the pressure-receiving surfaces of the housing 40 and piston assembly 45 on which the pressurized water acts, the contact area between the opening / closing door 25 and the pressing portion 44, the distance between the position where the pressing portion 44 contacts the opening / closing door 25 and the installation position of the frangible pin 57, the cross-sectional area of ​​the frangible pin 57, etc., so that the frangible pin 57 will break when a predetermined load is applied to the opening / closing door 25.

[0081] When the movement of the housing 40 relative to the inner tube 20 is restricted, the upper end surface of the rod 47 facing the pressure chamber 28 and the upper surface of the broken fragile member 50 become pressure-receiving surfaces that receive the pressure of the pressurized water in the pressure chamber 28, i.e., the pressure-receiving surface of the piston assembly 45, and the pressurized water supplied to the pressure chamber 28 acts on this pressure-receiving surface as shown by the arrow in Figure 10, generating a load that pressurizes the piston assembly 45 further downward relative to the housing 40.

[0082] When this load exceeds the breaking load of the frangible pin 55 that penetrates the rod 47 of the piston assembly 45 and the second cylindrical portion 42 of the housing 40 and the frangible pin 55 breaks, as shown in Figure 11, the upper end surface 46b of the piston 46 moves away from the step portion 43 of the housing 40, and the piston assembly 45 moves downward within the housing 40 until the lower end surface 46a of the piston 46 abuts against the lower step 41b of the housing 40.

[0083] The breaking load of the frangible pin 55 is set in advance based on the pressure of the pressurized water supplied from the working fluid supply device 18, the size of the pressure-receiving surface of the piston assembly 45 facing the pressure chamber 28, the cross-sectional area of ​​the frangible pin 55, the breaking load of the constricted portion 53, etc., so that the frangible pin 55 will break when pressurized water of a predetermined pressure is supplied from the working fluid supply device 18 after the constricted portion 53 breaks.

[0084] As shown in Figure 11, the upper end surface of the rod 47 facing the pressure chamber 28 and the upper end surface 46b of the piston 46 become pressure-receiving surfaces that receive the pressure of the pressurized water in the pressure chamber 28, and as the piston 46 moves downward within the housing 40 due to the load corresponding to the pressure acting on these pressure-receiving surfaces, the material 5 contained in the storage chamber S is pushed into the borehole 2 by the piston 46.

[0085] The material 5, such as bentonite, extruded into the borehole 2 rapidly swells when it comes into contact with groundwater, allowing a predetermined amount of backfilling of the borehole 2. The material 5 stored in the storage chamber S is not limited to pellet-shaped bentonite, and may be any material that has physical properties that allow it to backfill the borehole 2. Furthermore, in order to prevent the bentonite from swelling inside the housing 40, the material 5 may include a material that prevents groundwater that flows into the housing 40 when the opening / closing door 25 is opened from coming into contact with the bentonite, or a material that suppresses the swelling rate of the bentonite.

[0086] After the discharge of the material 5 is completed, the transport unit 16 is pulled up from the inside of the outer tube 10 to the ground and is recovered to be filled with the material 5 again (recovery step).

[0087] The transport unit 16 is lifted by inserting the lifting dock of the overshot assembly (not shown) into the outer tube 10 from above (ground) and moving it downward, thereby lifting the spear head 65 upward as shown by the arrow in Figure 12.

[0088] Furthermore, when the spear head 65 is pulled upward, the tubular member 64 is pulled upward, and the lower ends of the pair of slits 64a come into contact with the pair of latch portions 63, causing the upper ends of the pair of latch portions 63 to move radially inward against the spring force, and the pair of latch portions 63 are released from the engagement of the engagement grooves 14, so that the transport unit 16 can be recovered to the ground relatively easily.

[0089] When the transport unit 16 is retrieved, the lower end position of the outer tube 10 is adjusted again according to the depth to which the material 5 is to be released, as shown in (a) of Figure 7 (adjustment process). Specifically, the outer tube 10 is pulled up according to the amount of material 5 released into the borehole 2. Furthermore, the extension pipe 11 is removed on the ground as necessary.

[0090] Then, when the adjustment of the lower end position of the outer tube 10 is completed, the transport unit 16 with the material 5 accommodated in the accommodation chamber S is inserted into the outer tube 10 again.

[0091] In this way, by using the material discharge system 100 configured as described above, the above steps (adjustment step, movement step, supply step, extrusion step, and recovery step) are repeated in order, and the borehole 2 is efficiently backfilled.

[0092] According to the above embodiment, the following effects are achieved.

[0093] According to the material release system 100 of this embodiment, the downward movement of the conveying unit 16 is restricted to a predetermined depth by the outer tube 10 extending along the borehole 2, and then the piston 46 moves downward due to the pressure of pressurized water (working fluid) supplied to the pressure chamber 28 in the conveying unit 16, and the material 5 contained in the storage chamber S is pushed into the borehole 2 by the moved piston 46.

[0094] By having the outer tube 10 extend along the borehole 2 in this manner, when the conveying unit 16 containing the material 5 is lowered to a predetermined depth, and when the conveying unit 16 that has released the material 5 is raised and retrieved, the inner tube 20 of the conveying unit 16 does not come into contact with the wall of the borehole 2, thereby preventing the borehole 2 from collapsing.

[0095] This makes it possible to reliably transport and release the material 5 to a predetermined depth, and as a result, the borehole 2 can be backfilled efficiently.

[0096] The following modified examples are also within the scope of the present invention, and it is possible to combine the configuration shown in the modified example with the configuration described in the above embodiment, or to combine the configurations described in the different modified examples below.

[0097] In the above embodiment, the piston 46 is slidably held by the housing 40. Alternatively, the piston 46 may be slidably held by the inner tube 20, as in the modified example shown in FIG.

[0098] In the conveying unit 116 shown in Figure 13, the storage chamber S in which the material 5 is stored is defined by the inner surface 21a of the inner tube 20 and the lower end surface 46a of the piston 46, and the movement of the piston 46 is restricted by the lower step 21b and the upper step 21c of the inner tube 20.However, like the conveying unit 16 of the above embodiment, this conveying unit 116 is configured to include a cylindrical inner tube 20 that is formed so as to be able to move within the outer tube 10, a piston 46 provided within the inner tube 20, a storage chamber S that is defined within the inner tube 20 below the piston 46 and in which the material 5 is stored, and a pressure chamber 28 that is defined within the inner tube 20 on the opposite side of the piston 46 from the storage chamber S and to which the working fluid is guided.

[0099] Therefore, even in this modified example, when the constricted portion 53 of the fragile member 50 breaks, the load generated by the pressure of the working fluid in the pressure chamber 28 causes the piston 46 to move downward within the inner tube 20, and the piston 46 pushes the material 5 contained in the storage chamber S into the borehole 2.

[0100] In this modified example, the opening and closing door 25 is pushed open via the material 5 pressed downward by the piston 46, but in order to reliably open the opening and closing door 25, it is preferable to provide a rod-shaped member 49 (shown by a dashed line in Figure 13) extending downward from the piston 46 toward the location where the frangible pin 57 is provided.

[0101] Furthermore, if there is no risk of groundwater infiltrating into the storage chamber S, the opening and closing door 25 does not need to be provided, and in this case, the transport unit 116 can have a relatively simple configuration.

[0102] In this way, when the transport unit 116 shown in FIG. 13 is used, the borehole 2 can be backfilled efficiently, similar to the above embodiment.

[0103] In the above embodiment, the limiting step 13 provided on the restricting tube 12 of the outer tube 10 functions as a position switching unit that switches the position of the switching member 30 and also functions as a movement limiting unit that limits the downward movement of the conveying unit 16. Alternatively, the position switching unit and the movement limiting unit may be a locking groove 113 formed in a groove-like shape on the inner circumferential surface of the restricting tube 12 of the outer tube 10, as in the modified examples shown in Figures 14 to 16. Figure 14 corresponds to the state shown in Figure 8 above, and shows a state in which the downward movement of the conveying unit 216 is limited by the restricting tube 12 of the outer tube 10. Figure 15 is an enlarged cross-sectional view taken along line DD in Figure 14, and Figure 16 shows a state in which the discharge of the material 5 is completed and the movement restriction on the conveying unit 216 is released.

[0104] In this modified example, the inner surface of the regulating tube 12 is provided with a locking groove 113 formed as an annular groove instead of the limiting step 13 in the above embodiment, and the conveying unit 216 is provided with a switching member 130 that can engage with the locking groove 113 instead of the switching member 30 in the above embodiment.

[0105] 15, the switching member 130 is a member shaped to be insertable into a passage 129 having a substantially rectangular cross section that is formed radially through the second tubular portion 22 of the inner tube 20, and is constantly biased radially outward from the second tubular portion 22 by an elastic member such as a spring (not shown). The passages 129 are formed in two locations facing each other across the axis of the second tubular portion 22, and a switching member 130 is provided in each of the passages 129. Note that the passages 129 may be formed in three or more locations, in which case the passages 129 are evenly spaced in the circumferential direction.

[0106] Further, the switching member 130 is formed with a notched groove 131 that is open on the top surface and on the surface facing the pressure chamber 28. As shown in Figures 14 and 15, when the switching member 130 is pressed against the bottom surface of the locking groove 113 by the biasing force of an elastic member (not shown) and is engaged with the locking groove 113, the pressure chamber 28 is in a state of communication with the outside through the passage 129 and the notched groove 131, i.e., a state in which a working fluid such as pressurized water can be supplied into the pressure chamber 28 from the outside.

[0107] On the other hand, until the switching member 130 is engaged with the locking groove 113, that is, while the conveying unit 216 is moving downward within the outer tube 10, the switching member 130 abuts against the inner circumferential surface of the outer tube 10, thereby being pushed a predetermined length into the passage 129. The shape of the notched groove 131 that opens on the upper surface of the switching member 130 is formed so that the switching member 130 is covered by the passage 129 when the switching member 130 is pushed a predetermined length into the passage 129.

[0108] Therefore, while the conveying unit 216 is moving downward within the outer tube 10, the passage 129 is closed by the switching member 130, and liquid such as groundwater is prevented from flowing into the pressure chamber 28 through the passage 129. Note that, in a state in which the switching member 130 is pressed into the passage 129, a sealing member such as an O-ring may be provided on the outer peripheral surface of the switching member 130 or the inner peripheral surface of the passage 129 to seal a gap formed between the switching member 130 and the passage 129.

[0109] In this way, similar to the switching member 30 of the above embodiment, the switching member 130 is capable of switching the passage 129 from a closed state to an open state, and the position of the switching member 130 is switched from a closed position that closes the passage 129 to an open position that opens the passage 129 by the switching member 130 engaging with the locking groove 113 of the outer tube 10. Since the passage 129 is connected to the cutout groove 131 and placed in an open state by switching the position of the switching member 130 in this way, the locking groove 113 functions as a position switching part that switches the position of the switching member 130.

[0110] Further, the downward movement of the transport unit 216 is restricted by the engagement of the switching member 130 with the locking groove 113. That is, in this modification, the locking groove 113 provided in the regulating pipe 12 functions as a position switching portion that switches the position of the switching member 130, and also functions as a movement limiting portion that limits the downward movement of the transport unit 216. Note that a limiting step that limits the downward movement of the transport unit 216 may be provided in the regulating pipe 12 below the locking groove 113. In this case, the switching member 130 engages with the locking groove 113 almost simultaneously with the limiting step restricting the downward movement of the transport unit 216. In this case, the locking groove 113 with which the switching member 130 engages functions only as a position switching portion. Further, the downward movement of the transport unit 216 may be restricted by, for example, engaging a member equivalent to the switching member with a groove formed on the inner surface of the regulating pipe 12, separate from the locking groove 113.

[0111] Furthermore, the upward movement of the transport unit 216 is also limited by the engagement of the switching member 130 with the locking groove 113. That is, in this modified example, the locking groove 113 provided in the regulating tube 12 also functions as a movement limiting portion that limits the upward movement of the transport unit 216. Therefore, in this modified example, it is not necessary to provide the above-mentioned latch portion 63 in the transport unit 216, and it is also not necessary to form the locking groove 14 with which the latch portion 63 engages in the regulating tube 12. Note that if the latch portion 63 is not provided, the transport unit 216 may be suspended and lifted by a lifting device (not shown) via a cable (not shown). However, in order to reliably limit the upward movement of the transport unit 216, it is preferable to provide the above-mentioned latch portion 63 and the locking groove 14 with which the latch portion 63 engages.

[0112] In addition, a wire 136 for releasing the engagement with the locking groove 113 is attached to the switching member 130. The wire 136 is, for example, a steel wire rope, and as shown in FIG. 14 , one end is attached to the end surface of the switching member 130 facing the pressure chamber 28, and the other end is attached to the upper end of the rod 47 of the piston assembly 45.

[0113] When the fragile member 50 breaks and the piston assembly 45 moves downward, the wire 136 attached to the switching member 130 and the rod 47 in this manner becomes tense between the switching member 130 and the rod 47.

[0114] Then, when the piston assembly 45 moves downward within the housing 40 until the lower end surface 46a of the piston 46 abuts against the lower step 41b of the housing 40 (see FIG. 11), the tensile force acting on the switching member 130 via the wire 136 exceeds the biasing force of a spring (not shown) acting radially outward on the switching member 130, and the switching member 130 is drawn into the pressure chamber 28 and moves away from the locking groove 113, as shown in FIG. 16.

[0115] The path of the wire 136 is appropriately changed in direction by a pulley, a pin member, or the like so that the force with which the piston assembly 45 presses down on the wire 136 acts on the switching member 130 along the radial direction of the second cylindrical portion 22. The length of the wire 136 is set in advance so that when the lower end surface 46a of the piston 46 abuts against the lower step 41b of the housing 40, the switching member 130 moves away from the locking groove 113 and enters a disengaged state.

[0116] As a result, the engagement of the switching member 130 with the locking groove 113 is released, and the restriction on the upward movement of the transport unit 216 is lifted, making it possible to pull the transport unit 216 upward and collect it.

[0117] Thus, in this modified example, as in the above embodiment, the downward movement of the transport unit 216 is restricted by the locking groove 113, which functions as a movement restrictor, and the position of the switching member 130 is switched from the closed position to the open position by the locking groove 113, which functions as a position switching member, so that the working fluid is guided to the pressure chamber 28 through the passage 129. As a result, after the downward movement of the transport unit 216 is restricted at a predetermined depth by the outer tube 10 extending along the borehole 2, the piston 46 moves downward due to the pressure of the pressurized water (working fluid) supplied to the pressure chamber 28 in the transport unit 216, and the moved piston 46 pushes the material 5 stored in the storage chamber S into the borehole 2.

[0118] Furthermore, in the above embodiment, pressurized water is supplied to the pressure chamber 28 of the transport unit 16 through the outer tube 10, but pressurized water may also be supplied to the pressure chamber 28 through a water supply pipe directly connected to the transport unit 16. In this case, pressurized water is supplied from the working fluid supply device 18 through the water supply pipe when the transport unit 16 stops at a predetermined depth. Note that a valve device that allows pressurized water to be supplied through the water supply pipe when the transport unit 16 stops at a predetermined depth may be provided in the water supply pipe or in a passage that communicates the pressure chamber 28 and the water supply pipe in the transport unit 16.

[0119] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments.

[0120] In addition, in the above embodiment, the outer tube 10 is provided extending along the borehole 2, but if there is no risk of the borehole 2 collapsing, the outer tube 10 does not need to be provided, as in the reference example shown in Figure 17.

[0121] The material discharge system 200 of this reference example differs from the material discharge system 100 of the above embodiment in that it does not require the outer tube 10. In Fig. 17, components with the same reference numerals as those in the above embodiment have the same functions.

[0122] 17 is lowered to a predetermined depth in the borehole 2 by a lifting device (not shown) via a cable 70. Pressurized water is supplied to the pressure chamber 28 of the transport unit 316 through a water supply pipe 72 directly connected to the transport unit 316.

[0123] Therefore, once it is confirmed that the transport unit 316 has been lowered to a predetermined depth by the lifting device, pressurized water is supplied from the working fluid supply device 18 through the water supply pipe 72, and then, through a process similar to that of the above embodiment, the material 5 contained in the storage chamber S is pushed into the borehole 2 by the piston 46.

[0124] In this reference example, compared to the above embodiment, the outer tube 10 is not required, and the passage 29, the switching member 30, and the pair of latch portions 63 formed in the second tubular portion 22 are also not required, which reduces the cost required to backfill the borehole 2. Furthermore, similar to the above embodiment, the borehole 2 can be backfilled efficiently. [Explanation of symbols]

[0125] 100···Material Release System 2. Borehole 5...Material 10. Outer tube 13. Limit step (movement limiter, position changeover part) 16,116,216 Transport unit 18. Working fluid supply device 20···Inner tube 21b...Lower step (restriction part) 25···Opening and closing door 28. Pressure chamber 29,129a...Aisle 30... Switching member 40···Housing 45 Piston assembly 46 piston 50. Fragile member 55. Weak pin 57. Weak pin 61...Lid part 113 Locking groove (movement limiting portion, position switching portion) S...Containment Room

Claims

1. 1. A material discharge system for discharging material into a borehole, comprising: a cylindrical outer tube extending along the borehole; a conveying unit that is movable within the outer tube and whose downward movement is restricted by the outer tube at a predetermined depth; a working fluid supply device capable of supplying a working fluid to the transport unit, The transport unit includes: a cylindrical inner tube movable within the outer tube; a piston provided within the inner tube; a chamber defined in the inner tube below the piston, the chamber containing the material; a pressure chamber defined within the inner tube on the opposite side of the piston from the accommodation chamber, and into which the working fluid is guided; the material in the storage chamber is forced into the borehole by the piston moving downward due to the pressure of the working fluid in the pressure chamber; Material release system.

2. the conveying unit further includes a switching member that can switch a passage that guides the working fluid to the pressure chamber from a closed state to an open state, the switching member opens the passage when the downward movement of the conveying unit is restricted by the outer tube. The material delivery system of claim 1 .

3. the conveying unit further includes a switching member that switches its position from a closing position that closes the passage that guides the working fluid to the pressure chamber to an opening position that opens the passage, the outer tube has a movement limiting portion that limits downward movement of the conveying unit and a position switching portion that switches the position of the switching member, the downward movement of the conveying unit is restricted by the movement restricting portion, and the position of the switching member is switched from the closed position to the open position by the position switching portion, whereby the working fluid is guided to the pressure chamber through the passage. The material delivery system of claim 1 .

4. The transport unit includes: an opening / closing door that is provided to be able to open and close a lower opening of the inner tube; a housing movably disposed within the inner tube and accommodating the piston; the pressure chamber is defined by at least the inner tube and the housing, The door is pushed open by the housing, which moves downward due to the pressure of the working fluid in the pressure chamber.

4. A material delivery system according to any one of claims 1 to 3.

5. the accommodating chamber is defined by the housing and the piston, The inner tube is provided with a limiting portion that limits downward movement of the housing after the opening and closing door is pushed open, The material in the storage chamber is pushed into the borehole by the piston moving downward due to the pressure of the working fluid in the pressure chamber within the housing whose downward movement is restricted by the restricting portion.

5. The material delivery system of claim 4.

6. 1. A method of discharging material into a borehole, comprising: an adjusting step of adjusting a lower end position of a cylindrical outer tube extending along the borehole according to a depth to which the material is to be discharged; a moving step of inserting a conveying unit into the outer tube and moving it downward until its downward movement is restricted by the outer tube, the conveying unit having a cylindrical inner tube movable within the outer tube, a piston provided within the inner tube, a storage chamber defined within the inner tube below the piston and for storing the material, and a pressure chamber defined within the inner tube on the opposite side of the piston from the storage chamber and for introducing a working fluid; a supply step of supplying the working fluid to the transport unit; an extrusion step of extruding the material in the storage chamber into the borehole by moving the piston downward using the pressure of the working fluid in the pressure chamber. Material release method.

7. The method further includes a recovery step of recovering the transport unit from the outer tube, The adjusting step, the moving step, the supplying step, the pushing step, and the collecting step are repeatedly performed in this order.

7. The material release method of claim 6.

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