JP2007046301A - Drilling tool and chemical feeding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent damage such as a crack from being caused by a drilling operation, even in the use of a casing pipe made of a synthetic resin. <P>SOLUTION: This drilling tool 11 has the casing pipe 41 which is positioned on the side of the outer periphery of a rod 21 so as to prevent a collapse of a wall of a drilled hole. In the drilling tool 11, a leading end of the rod 21 is disconnectably connected to a back end of a drilling bit member 31 by means of screws 23 and 32a; a leading end of the casing pipe 41 is provided with a leading-end sleeve 51 which is to be fitted in a relatively movable state to a fitting shaft part 34 of a backside part of the member 31; fitting structures 38 and 52, which are radially fitted into each other so as to be prevented from coming off from each other, and which make the leading-end sleeve follow the drilling bit member, are provided between the leading-end sleeve 51 and the shaft part 34; and a buffering gap 52a, which enables the leading-end sleeve 51 to relatively move on the member 31, is formed between the fitting structures 38 and 52. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a drilling tool used in tunnel construction, foundation work, reinforcement work, and the like, and more particularly to a drilling tool that can withstand use even when a casing pipe is made of a synthetic resin.

  An example of the casing pipe that may be made of a synthetic resin is an excavation tool disclosed in Patent Document 1 below. This excavation tool is structured to transmit thrust and impact in the axial direction to the casing pipe. This excavation tool is connected to the casing pipe to which thrust and impact are transmitted and the inside of the casing pipe. A rod that is disposed on the core and transmits thrust and striking force in the axial direction and rotational force; a drilling tool main body attached to the tip of the rod; and a tip of the drilling tool main body. A drilling tool comprising a drilling bit that is mounted while being constrained to rotate with respect to the drilling tool body, and has a cylindrical shape that is movable in an axial direction relative to the casing pipe and rotatable about the axis at the tip of the casing pipe. The casing top is attached so as to be fitted to the drilling tool body, and the casing top is always built in the drilling hole so as to surround the drill bit. Mukoto is configured to allow.

  In this configuration, the casing top is attached so as to be movable in the axial direction with respect to the casing, so that excessive resistance does not act on the casing pipe during installation, and the casing pipe is of low strength such as resin. It is said that it may be.

  However, thrust and striking directly act on the casing pipe, and even if a cushioning material is interposed, a great load is applied, which may cause cracks. In particular, when the object to be drilled is a hard rock mass, the load becomes very large, and a tool having a configuration as in Patent Document 1 cannot be drilled.

  Moreover, the excavation tool of patent document 1 is for forming a drilling hole, and cannot inject | pour a chemical | medical solution in order to reinforce (improve) or waterproof a ground and a rock. For this reason, a separate injection tube was required. In addition, since the chemical injection operation must be performed after the drilling operation is completed, the operation is complicated.

JP 2003-172089 A

  Accordingly, the main object of the present invention is to eliminate the possibility of damaging the casing pipe and to facilitate the chemical liquid injection operation.

  For this purpose, a rod for transmitting power for drilling, a drill bit member provided at the tip of the rod for drilling, and a hole wall drilled at the outer peripheral side of the rod A drilling tool having a casing pipe for preventing collapse of the rod, wherein the rod is detachably connected to the drill bit member between the tip end portion of the rod and the rear end portion of the drill bit member. A structure is provided, and at the tip of the casing pipe, a tip side portion of the tip sleeve is relatively movable with respect to a fitting shaft portion formed on an outer periphery of a rear side portion of the drill bit member. A front end sleeve to be fitted is provided, and the front end sleeve and the fitting shaft portion of the drilling bit member are fitted to each other in the radial direction to prevent detachment. A fitting structure is provided to follow the fitting structure. The a drilling tool where gaps are formed in the buffering of the relative movable tip sleeve on drilling bit member.

  That is, the rod for transmitting the power for cutting applies a hit while rotating with respect to the drilling bit member to perform drilling. At this time, the tip sleeve is fitted to the outer periphery of the fitting shaft portion of the drilling bit member so as to be relatively movable, but the fitting that prevents the tip sleeve and the fitting shaft portion from coming off is fitted. Since the structure is provided, the tip sleeve moves following the drill bit in accordance with the drilling operation of the drill bit member. However, the fitting structure has a buffering gap that allows the tip sleeve to move relative to the drill bit member, so that vibration due to impact is reduced and the tip sleeve is connected to the rear end of the tip sleeve. The load on the casing pipe can be reduced.

  For this reason, even if the casing pipe is made of a synthetic resin such as vinyl chloride, it is possible to avoid unexpected damage such as cracking.

  In addition, after drilling, the rod may be separated from the drill bit member in the detachable structure, and the rod may be extracted leaving the drill bit, casing pipe, and tip sleeve.

Here, the following aspects can be adopted for each of the above components.
One of the aspects is that a conduction hole portion penetrating in the length direction is formed in the axial center portion of the rod, and a central hole communicating with the conduction hole portion is formed at a central portion in the axial direction of the drill bit member. And a nozzle hole extending from the tip of the central hole to the tip of the drill bit member. The central hole or the nozzle hole has a nozzle hole from the nozzle hole side. A check valve is provided to prevent the intrusion of the object.
That is, when drilling, fluid such as compressed air is allowed to flow through the conducting hole of the rod, the center hole of the drill bit member, and the nozzle hole, and the chemical solution is injected through a chemical solution such as ground improvement instead of the fluid. be able to. Further, when no fluid is allowed to flow, the check valve can prevent intrusion of objects such as mud and sand from the nozzle hole.

In another aspect, the fitting structure includes a convex portion and a concave portion, and the convex portion includes a sphere that can roll.
In other words, since the convex portion is a spherical body that can be rolled between the convex portion and the concave portion that are fitted to each other to prevent detachment, the impact can be reduced when the convex portion and the concave portion collide. For this reason, a further buffering effect can be expected.

The other one of the aspects is provided with a seal member that seals between the fitting shaft portion of the drill bit member and the inner peripheral surface of the tip sleeve at two positions sandwiching the fitting structure in the axial direction. It is.
That is, since the tip sleeve is connected to the fitting shaft portion via the seal member, the tip sleeve does not rattle. Further, mud or sand can be prevented from entering between the fitting shaft portion and the tip sleeve, and the fitting structure for buffering can be protected.

In another aspect, the casing pipe is made of resin.
That is, even if the casing pipe is built and buried as it is, there is no hindrance to the excavation work to be performed later, and an easy work with reinforcement and waterproofing can be expected.

In another aspect, the attachment / detachment structure is attachable / detachable by rotation, and another rod is connected via a coupling member after the rod, and between each rod and the coupling member. In addition, a thread is formed in a direction opposite to the direction enabling disengagement in the attachment / detachment structure, and an engagement groove along the circumferential direction is formed on the inside of the rod or the coupling member. The coupling member or the rod located outside is formed with a through hole corresponding to the engagement groove when the rod and the coupling member are connected, and a pin is formed with respect to the through hole. By being inserted, the rod and the coupling member are connected so as to be non-rotatable.
In other words, a hole is made by striking the rod while rotating in a direction opposite to the direction that enables the rod to be detached with the detachable structure, and after forming a predetermined hole, the detachable structure with respect to the rod Since the rods and the couplings are coupled to the engaging grooves, the through holes, and the pins so as not to rotate relative to each other, the rods can be removed from the drill bit member and collected.

In another aspect, the casing pipe has an injection hole with a check valve.
That is, if a desired hole is drilled and the rod is removed, then a chemical liquid injection pipe is inserted in place of the rod to inject the chemical liquid, the chemical liquid ejected from the injection pipe is injected through the injection hole of the casing pipe. Perform the desired action. Since the injection hole has a check valve, it is possible to prevent mud or sand from entering the casing pipe during drilling.

Another means is a drilling method in which drilling is performed using the drilling tool, the rod is separated from the drill bit member, and the rod is removed leaving the casing pipe.
In other words, the rod is drilled and collected, and the others including the casing pipe are buried, so there is only one member to be collected, and it is simple and does not require labor. Efficiency can be improved.

Another means is a drilling step performed using the drilling tool having the conduction hole portion, the central hole portion, and the nozzle hole, and the rod of the drilling tool is formed with respect to the drilling hole formed in the drilling step. This is a chemical solution injection method in which a chemical solution injection process performed by injecting a chemical solution from a conduction hole is performed alternately or simultaneously.
That is, since the hole drilling and the chemical liquid injection can be performed in synchronization, the working efficiency can be significantly improved as compared with the case where the chemical liquid injection is performed by inserting a chemical liquid injection tool again after the hole has been drilled once.

  As described above, according to the present invention, the tip sleeve is provided at the tip of the casing pipe so that the vibration for drilling transmitted to the drill bit member via the rod is not directly transmitted to the casing pipe. A buffering fitting structure is provided between the tip sleeve and the drill bit member. For this reason, a possibility that a casing pipe may be damaged by rotation and striking for drilling can be eliminated. That is, the casing pipe only needs to have a strength that prevents the hole wall from collapsing, and it is not necessary to use a steel pipe. Moreover, the rod is extracted after the drilling operation. As a result, even if the casing pipe is buried, if the casing pipe is not made of steel but is made of synthetic resin or paper, there is no influence on the subsequent work such as excavation, and work efficiency can be improved.

  The power for drilling is directly applied to the rod and the drill bit member provided at the tip of the rod, so that it is possible to inject chemical into the rod and drill bit member. By providing such a configuration, it is possible to inject the chemical liquid while drilling, and the workability of the chemical liquid injection is greatly improved.

An embodiment for carrying out the present invention will be described below with reference to the drawings.
FIG. 1 is a sectional view of the drilling tool 11, and FIG. 2 is an exploded view thereof. As shown in these drawings, the drilling tool 11 includes a rod 21 that transmits power for drilling, a drill bit member 31 that is detachably attached to the tip of the rod 21, and performs the drilling. A casing pipe 41 which is positioned on the outer peripheral side of the rod 21 to prevent the hole wall drilled from collapsing, and a tip sleeve 51 which is provided at the tip of the casing pipe 41 and which is interposed between the drill bit member 31; Have

  The drilling tool 11 has a structure in which drilling is performed by the rotational force and striking force transmitted to the drilling bit 31 through the rod 21, and the tip sleeve 51 and the casing pipe 41 are drilled. Intrudes into the drilling hole.

Each part will be described in turn.
The rod 21 is connected to the tip of a shank rod (not shown) in the main body hammer mechanism of the percussion machine. The rod 21a is connected to the drill bit member 31, and the tip rod 21a. There is an additional rod 21b that is sequentially added to the rear of the rear. Each of them has a cylindrical shape with a predetermined length, and has a conduction hole portion 22 penetrating in the length direction at the axial center portion, and male screws 23 and 23 for connection are formed at both ends. The male screw 23 is a left-hand screw. That is, the rotation in the direction in which the rotation to the left is tightened. In the drawing, a taper screw is shown as an example, but a rope screw or a high lead screw may be used.

  In the tip rod 21a, one end on the side connected to the drill bit member 31 is formed only by the male screw 23, but the other end is added to the male screw 23 at both ends of the rod 21b. As described above, the engagement groove 24 is also formed at the tip of the male screw 23.

  That is, one engagement groove 24 having a U-shaped cross section is formed in the circumferential direction at the tip of the male screw 23 formed over a predetermined length range. The tip rod 21a, the extension rod 21b, and the extension rod 21b are connected to each other by a cylindrical coupling member 26 having both ends of an internal thread 25 screwed to the external thread 23. A through hole 27 is formed at a position corresponding to the engagement groove 24 at the time of connection. Two through holes 27 are formed in parallel to one engagement groove 24, that is, a total of four through-holes 27 are formed in one coupling member 26.

  The pins 28 are inserted into the through holes 27 after being connected by screwing (see FIG. 4). Even if the rod 21 is removed from the coupling member 26 due to the insertion of the pin 28, that is, in the right direction, the pin 28 inserted in the through hole 27 remains engaged with the engagement groove 24. Rotation in the right direction is prevented, and it is prevented from coming off. In addition, it is preferable to use a split pin as the pin.

  The drill bit member 31 includes a substantially cylindrical body member 32 to which the rod 21 is connected, and a bit member 33 that is integrally fixed to the end of the body member 32. The main body member 32 has a female screw 32a into which the male screw 23 of the tip rod 21a is screwed at the rear end portion, and the tip portion is inserted into the bit member 33 and fixed in a non-rotatable state. A portion of the main body member 32 protruding from the bit member 33 is a fitting shaft portion 34.

  The bit member 33 has a diameter larger than that of the main body member 32, the tip portion is formed in an appropriate shape, and a chip 35 made of cemented carbide is fixed. The bit member 33 is formed with a central hole portion 36b that communicates with a central hole portion 36a formed in the axial center portion of the main body member 32, and a plurality of nozzle holes 36c are formed ahead of the central hole portion 36b. Is formed.

  Fluids such as air, water, and chemicals injected through the conduction hole 22 in the rod 21 or through other members pass through the center holes 36a and 36b and the injection hole 36c. For this reason, a check valve 37 is provided in the central hole portions 36a and 36b. The check valve 37 can be composed of a ball 37a and a torsion coil spring 37b that urges the ball 37a as shown in the figure.

  Further, a convex portion 38 is formed between the check valve 37 and the female screw 32a as a component of a fitting structure to which the tip sleeve 51 is attached in a relatively movable state. The relative movement is set so as to be performed in an appropriate range in the length direction and the circumferential direction of the distal end sleeve 51. A plurality of convex portions 38 are formed in the circumferential direction, for example, three, four, and the like.

  In this example, the convex portion 38 is formed of a rollable sphere 38a. Further, the sphere 38a can freely move in and out.

  That is, the sphere 38a is held in a holding hole 34a formed in the fitting shaft portion 34, and a short cylindrical support ring 38b housed so as to be positioned on the inner peripheral side of the holding hole 34a, and this And a spring 38c that urges the support ring 38b to be positioned below the holding hole 34a. A taper surface 38d is formed on the outer spring surface of the support ring 38b on the side opposite to the spring, and when the support ring 38b is displaced rearward from the position where the support ring 38b is displaced toward the tip side, the spherical body 38a is pressed toward the outer circumference side. And is configured to move. In the drawing, reference numeral 39 denotes a stopper for restricting the position of the support ring 38b.

  The tip sleeve 51 fits on the outer periphery of such a fitting shaft portion. The tip sleeve 51 has a recess 52 at a portion corresponding to the sphere 38a on the inner peripheral surface. The recess 52 has a size having a buffering gap 52 a that allows the distal end sleeve 51 to relatively move on the fitting shaft portion 34.

  Sealing members 53 and 54 for sealing between the fitting shaft portion 34 are provided at two positions on the inner peripheral surface of the distal end sleeve 51 that sandwich the concave portion 52 in the length direction.

  Further, at the distal end portion of the distal end sleeve 51, a meshing portion 51a that meshes with a meshing portion 33a formed at the rear end portion of the bit member 33 in the drill bit member 31 so as to be relatively movable is formed.

  On the other hand, a connecting screw portion 51b for connection is formed at the rear end portion of the front end sleeve 51, and the casing pipe 41 is connected thereto.

  In order to fit the tip sleeve 51 to the fitting shaft portion 34, the support ring 38b is pushed toward the tip direction using an appropriate jig, and in this state, the tip portion of the tip sleeve 51 is pushed into the fitting shaft. After being inserted into the portion 34, the pressing of the support ring 38b by the jig may be released. Then, the support ring 38b is displaced rearward along with the elastic return of the spring 38c, and the sphere 38a protrudes to the outer peripheral side. In other words, the sphere 38a fits in the recess 52 and enters a fitted state.

  The casing pipe 41 is made of a synthetic resin such as vinyl chloride and has a cylindrical shape with a predetermined length. A first screw portion 41a that is screwed into the connection screw portion 51b is formed at the tip, and a second screw portion (not shown) that can be screwed into the first screw portion 41a is formed at the rear end. In the formed structure, it is used by sequentially adding.

  Moreover, in order to inject | pour a chemical | medical agent in the casing pipe 41, as shown in FIG. 5, the several injection hole 43 with the non-return valve 42 is formed for every suitable space | interval. For example, as shown in FIG. 5A, the injection hole 43 with the check valve 42 includes a ball 42 a and a spring 42 b that biases the ball 42 a and an inner hole 42 c that is positioned on the inner peripheral side of the casing pipe 41. And the outer hole 42d located on the outer peripheral side. At this time, in order to prevent the passage of mud or the like from the outside to the inside while allowing the passage of fluid from the inside to the outside, the inner hole 42c is held by the ball 42a. Further, the check valve 42 may be made of one rubber as shown in FIG. That is, the check valve 42 includes a cylindrical portion 42e attached to the hole, a retaining flange 42f formed at the lower end of the cylindrical portion 42e (the inner periphery of the casing pipe 41), And a plurality of valve plates 42g that can be opened and closed, formed at the upper end of the cylindrical portion 42e (the outer periphery of the casing pipe 41 is a flange).

  In the drilling tool 11 configured as described above, the counterclockwise rotational force and impact force are applied to the drilling bit member 31 from the percussion machine with the rod 21 connected to the drilling bit member 31 as shown in FIG. When transmitted, as shown in FIG. 6, the drill bit member 31 receives the rotational force and the striking force and cuts into the ground or rock. At this time, it is the tip sleeve 51 that is in contact with the drill bit member 31 that receives the rotational force and the striking force. The tip sleeve 51 is in contact with the fitting structure composed of the convex portion 38 and the concave portion 52. The sealing members 53 and 54 are used. Since there is a gap 52 a (margin, play) between the convex portion 38 and the concave portion 52, vibration due to rotational force or striking force is mitigated, and the casing connected to the rear end portion of the leading end sleeve 51. The load applied to the pipe 41 can be reduced.

  In addition, since the convex portion 38 can roll, the impact at the time of the collision between the convex portion 38 and the concave portion 52 can be mitigated, so that the load applied to the casing pipe 41 is further reduced.

  Further, since the distal end sleeve 41 is connected to the fitting shaft portion via the seal members 53 and 54, the distal end sleeve 51 does not rattle. In addition, mud or the like can be prevented from entering between the fitting shaft portion 34 and the tip sleeve 51, and the fitting structure for buffering can be protected.

  In addition, after completion of the drilling operation and the like, as shown in FIG. 7, the rods are all united by applying a counterclockwise rotation force, that is, clockwise, as shown in FIG. The rod 21a can be easily separated from the drill bit member 31. The extracted rod 21 can be separated for each member by removing the pin 28 inserted into the through hole 27 of the coupling member 26.

An example of work using the above drilling tool will be described below.
(Working example 1)
In the case of injecting a chemical solution while drilling, as shown in FIG. 8, first, a hole having a predetermined depth (a drilling process) is performed while injecting air or water from the nozzle hole (a). After stopping the hole operation, a desired chemical solution is injected from the injection hole 36c instead of air or water (chemical solution injection step) (b). Alternatively, the hole drilling (drilling process) and the chemical liquid injection (chemical liquid injection process) are performed simultaneously.
Such operations are sequentially repeated to perform drilling and chemical injection to a predetermined depth (c).
Finally, the rod is rotated to the right to collect only the rod (d).

(Working example 2)
When a chemical solution injection (chemical solution injection step) is performed after a predetermined depth of drilling (drilling step), first, as shown in FIG. Drill holes (a, b). Next, the rod is rotated to the right to collect only the rod (c). Subsequently, the injection pipe 61 for injecting chemical liquid is inserted instead of the rod 21 and chemical injection is performed using the injection pipe 61 (d). The chemical liquid is ejected from an injection hole 43 with a check valve 42 provided in the casing pipe 41.

The drilling operation and the chemical solution injection operation are performed as in the above example.
In the drilling operation, since the load applied to the casing pipe 41 can be suppressed as described above, unexpected damage such as cracking of the casing pipe 41 can be avoided.

  Further, since the conducting hole 22 is formed in the rod 21 and the central holes 36a and 36b and the injection hole 36c are formed in the drilling bit member 31, the drilling bit member 31 is formed while drilling or alternately with the drilling. It is also possible to inject chemical liquid, and work efficiency can be improved.

  Furthermore, since the casing pipe 41 to be buried after the work is made of synthetic resin, there is no influence on the work such as excavation and the work efficiency can be improved.

  Moreover, since the casing pipe 41 has the injection hole 43 with the check valve 42, when performing chemical | medical solution injection | pouring after drilling, the operation | work can be performed with the casing pipe 41 being buried without extracting. That is, the work can be simplified.

  Hereinafter, other embodiments will be described. In addition, about the site | part same or equivalent to the said structure, the same code | symbol is attached | subjected and the detailed description is abbreviate | omitted.

  FIG. 10 is an example showing a case where the convex portion 38 as a component of the fitting structure formed between the fitting shaft portion 34 and the tip sleeve 51 is not freely movable in and out.

  That is, a plurality of recesses 34b are formed and formed in the circumferential direction in the convex portion forming position in the fitting shaft portion 34, and the lower half of the spherical body 38a as the convex portion 38 is formed. The corresponding position is set to a thickness at which a predetermined recess 52 can be formed, and a hole 55 penetrating inward and outward is formed in this portion. A lid member 56 is fixed to the hole 55. That is, when fitting the fitting shaft portion 34 and the tip sleeve 51, the lid member 56 is not attached and the hole 55 is opened, and the tip sleeve 51 is fitted to the fitting shaft portion 34. Thereafter, the sphere 38 a is received in the recess 34 b through the hole 55. If the lid member 56 is fixed after the spherical body 38a is accommodated, the distal end sleeve 51 is prevented from coming off from the fitting shaft portion 34 and can be buffered.

  FIG. 11 also shows an example in which the convex portion 38 as a component of the fitting structure formed between the fitting shaft portion 34 and the tip sleeve 51 is not freely movable in and out. The fixing work of the hole 55, the lid member 56, and the lid member 56 in the case of the example shown in FIG.

  That is, a holding hole 34a having a shape penetrating inward and outward is formed at the projecting portion forming portion of the fitting shaft portion 34, and the rear side from the holding hole 34a, that is, the female screw 32a for connecting the rod is more than the front side. Large diameter is set. A cylindrical support member 38e that supports a spherical body 38a as the convex portion 38 is fixed to the portion formed to have a large diameter.

  The tip sleeve 51 is fixed to the fitting shaft portion 34. First, the tip sleeve 51 is fitted to the fitting shaft portion 34, and then the spherical body 38a is accommodated in the holding hole 34a. Subsequently, the support member 38 e is fixed to the large-diameter portion of the main body member 32 constituting the fitting shaft portion 34. Then, the spherical body 38a is accommodated in the holding hole 34a and the recess 52, and the tip sleeve 51 is prevented from being detached and can be buffered.

In the correspondence between the configuration of the present invention and the configuration of the above-described embodiment,
The attachment / detachment structure of the present invention corresponds to the male screw 32 and the female screw 32a of the tip rod 21a in the above-described embodiment,
Similarly,
The fitting structure corresponds to the convex part 38 and the concave part 52,
The present invention is not limited to the configuration of the above-described one form, and various other forms can be adopted.

  For example, the attachment / detachment structure may not be configured only by screws as described above, but may be configured to have a groove with a specific shape and attach / detach by a predetermined operation such as appropriate rotation and tension. .

  Moreover, although the fitting structure showed the example which provided the convex part and the front-end | tip sleeve on the fitting shaft part side, a convex part and a recessed part may be arrange | positioned reversely. In addition to the spherical body, for example, an E-ring-shaped member can be fixed to the tip sleeve, and the protrusion located on the inner peripheral side of the member can be a convex portion of the fitting structure.

Sectional drawing of a drilling tool. Sectional drawing of the decomposition | disassembly state of a drilling tool. Structure explanatory drawing of an extension rod and a coupling member. Sectional drawing of the connection state by a coupling member. The partial expanded sectional view of a casing pipe. Sectional drawing of an action state. Sectional drawing of an action state. Explanatory drawing which shows a work process. Explanatory drawing which shows a work process. Sectional drawing of the drilling tool which concerns on another example. Sectional drawing of the drilling tool which concerns on another example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Drilling tool 21 ... Rod 22 ... Conduction hole 23 ... Male screw 24 ... Engagement groove 26 ... Coupling member 27 ... Through-hole 28 ... Pin 31 ... Drilling bit member 32a ... Female screw 34 ... Fitting shaft part 36a, 36b ... Central hole 36c ... Injection hole 37 ... Check valve 38 ... Projection 38a ... Sphere 41 ... Casing pipe 42 ... Check valve 43 ... Injection hole 51 ... Tip sleeve 52 ... Recess 52a ... Clearance 53, 54 ... Seal member

Claims (9)

A rod that transmits power for drilling, a drill bit member that is provided at the tip of the rod to drill, and a casing that is positioned on the outer peripheral side of the rod and prevents collapse of the drilled hole wall A drilling tool having a pipe,
An attachment / detachment structure for detachably connecting the rod to the drilling bit member is provided between the tip of the rod and the rear end of the drilling bit member,
A tip sleeve that fits at the tip of the casing pipe so that the tip side portion of the tip sleeve can move relative to the fitting shaft portion formed on the outer periphery of the rear portion of the drill bit member. Is provided,
Between the tip sleeve and the fitting shaft portion of the drill bit member, there is provided a fitting structure that fits each other in the radial direction and prevents the tip sleeve from following the drill bit member.
A drilling tool in which a gap for buffering is formed in the fitting structure so that the tip sleeve can be relatively moved on the drill bit member. A conduction hole portion penetrating in the length direction is formed in the axial core portion of the rod,
A central hole portion that communicates with the conduction hole portion is provided from the rear end in the central portion in the axial direction of the drill bit member, and the front end portion of the drill bit member opens from the front end of the central hole portion. As the nozzle hole is extended,
2. The drilling tool according to claim 1, wherein the central hole or the injection hole is provided with a check valve for preventing an object from entering from the injection hole side. The fitting structure is composed of a convex part and a concave part,
The drilling tool according to claim 1 or 2, wherein the convex portion is formed of a rollable sphere. The sealing member which seals between the fitting axial part of a drilling bit member, and the internal peripheral surface of a front-end | tip sleeve is provided in two positions which pinch | interpose the said fitting structure in an axial direction. A drilling tool according to any one of the above. The drilling tool according to any one of claims 1 to 4, wherein the casing pipe is made of resin. The detachable structure is detachable by rotation,
After the rod, another rod is connected via a coupling member,
Between each rod and the coupling member, a screw is formed in a direction opposite to the direction allowing the detachment by the detachable structure,
An engagement groove extending in the circumferential direction is formed in the rod or the coupling member located on the inner side, and the rod and the coupling member are arranged on the outer side of the coupling member or the rod. A through hole corresponding to the engagement groove is formed when connected,
The drilling tool according to any one of claims 1 to 5, wherein the rod and the coupling member are connected so as to be able to prevent rotation by inserting a pin into the through hole. The drilling tool according to any one of claims 1 to 6, wherein the casing pipe has an injection hole with a check valve. Drilling hole drilling using the drilling tool according to any one of claims 1 to 7, separating the rod from the drill bit member, and removing the rod leaving the casing pipe. Construction method. Drilling step performed using the drilling tool according to any one of claims 2 to 7,
A chemical solution injection method in which a chemical solution injection step performed by injecting a chemical solution from a conduction hole portion of a rod in the drilling tool is alternately or simultaneously performed with respect to the hole formed in the drilling step.

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