JPH08189035A - Soil-nail collet, soil nail and device for driving-in thereof - Google Patents

Abstract

PURPOSE: To impart thrust to the head of a soil nail during driving in. CONSTITUTION: The head 2A of a drain nail 2 is loaded into a cylinder 40, together with a collet 21. The collet 21 comprises first and second collets 23, 24. The first collet 23 consists of two members 23A which are separably coupled together and removably attached to the head 2A. The second collet 24 is held by a backplate 24 located on the side of a cylinder 40, and locks the first collet 23. The first collet 23 is advanced into the cylinder 40 by compressed air 43 during driving in, and thrust is transmitted to the head 2A by a thrust imparting portion 27. Thereafter, when colliding with a breaking projection 31 provided inside a cover 41, the first collet is broken apart, separated from the head 2A and left inside the cover 41. The drain nail 2 is made to fly out of the cover 41 and driven into the ground.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soil nail, a collet for soil nail, and a nail nail driving device which are driven into the ground for improving the ground.

[0002]

2. Description of the Related Art Slope improvement methods such as densification method and consolidation method are used as a ground improvement method for protecting a slope on a terrain having a slope or for taking measures against soft ground regardless of the presence or absence of a slope. Various construction methods such as a chemical method and a soil nail method have been conventionally known. The densification method is a method of mechanically compacting the ground mainly by vibration, impact or the like. The consolidation method is
It is a method of injecting a binding substance such as cement or lime into the ground to solidify. In the soil nail method, a rod-shaped body having only a reinforcing function or a pipe having both a reinforcing function and a draining function (usually these are collectively referred to as soil nails, particularly those having a draining function are called drain nails). It is a method of directly driving into the ground. The structure of the drain nail is a perforated tube having holes of appropriate size on the peripheral surface, or a plurality of axial core materials are arranged in a cylindrical shape at appropriate intervals instead of the perforated tube, and the wire is provided on the outer periphery thereof. It is known that spirally wound.

[0003]

However, all of the conventional soil nail driving devices adopt a rear driving method in which thrust is applied to the soil nails from the rear and the soil nails are driven into the soil, so that the ground resistance is large. There was a problem that a large compressive force was applied to the soil nail, causing it to buckle and break easily.
Therefore, since a large thrust cannot be applied and a large buckling strength is required, there is a drawback that the material selection of the soil nail itself is restricted and the degree of freedom in design is small.

Therefore, as a method for solving such a problem, as disclosed in Japanese Unexamined Patent Publication No. 3-69718, a front nailing device for nail nailing is designed to apply thrust to the head. Is proposed. In this soil nail driving device, the head of the soil nail is mounted in a cylinder together with a cylinder called a sabot, and a predetermined thrust is transmitted to the head through the cylinder, so that the soil nail is moved into the ground. It is something to drive in. In such a device, since the thrust is directly applied to the head of the soil nail,
There is an advantage that buckling strength is not required and flexibility can be given to material selection and design of soil nail.

However, in the above-mentioned soil nail driving device, it is necessary to penetrate the head of the soil nail into the cylindrical body, so that the work is troublesome and it is difficult to reliably transmit the thrust. There was a problem.
That is, a ring-shaped divided elastically deformable frustoconical portion is provided on the front side of the cylindrical body, and the tip of this frustoconical portion is brought into contact with the shoulder portion formed on the head of the soil nail to transmit thrust. Therefore, if the strength and rigidity of the frusto-conical portion are low, the thrust force cannot be transmitted due to buckling or damage, and if the strength and rigidity are increased, the soul nail is inserted into the frusto-conical portion. Therefore, a large force is required, and when the soil nail is fired from the driving device, the frusto-conical portion opens and is not damaged, which gives a braking force to the soil nail. Therefore, it is not practical because it is difficult to select and design the material of the cylindrical body.

The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to make it possible to reliably apply thrust to the head of a soil nail at the time of driving. Is to provide a collet for. Another object of the present invention is to provide a soil nail provided with a collet that can reliably apply thrust to the head of the soil nail when driven. Furthermore, the present invention is to provide a soil nail driving device that applies thrust to the head of a soil nail and drives the soil nail.

[0007]

In order to achieve the above object, a collet for soil nails according to the present invention comprises a first collet attached to the head of the soil nail and a second collet located behind the first collet. A collet, and the first collet is constituted by a plurality of members provided with a thrust applying portion for transmitting a thrust to the head and disassembled and coupled,
The collet is composed of a tubular body through which the head slidably passes, and the second collet is detachably engaged with the second collet so that the collet is ruptured by the thrust force when the soil nail is driven. It is characterized in that a connecting portion is provided. Further, the soul nail collet according to the present invention is characterized in that the thrust transmission portion is formed by a serrated annular projection. Further, the soul nail collet according to the present invention is characterized in that a convex portion that disassembles the first collet by contacting a disassembly projection provided on the driving device side is provided on the front surface of the first collet. To do. The soul nail collet according to the present invention is characterized in that a plurality of members constituting the first collet are detachably coupled by engagement of the engagement piece and the engagement recess. Further, the soil nail according to the present invention has a head portion having a conical tip portion and a thrust receiving portion provided on the circumferential surface, a drain portion continuously provided at the rear portion of the head portion, and a detachable portion on the head portion. And a collet that is inserted into the soil nail driving device together with the head when driven, and a thrust applying portion that engages the thrust receiving portion and transmits the thrust to the head is provided. A first collet composed of a plurality of members that can be disassembled, and a cylindrical body through which the head slidably penetrates and is fixed in a soil nail driving device to fix the first collet. It is characterized by being configured with a second collet that is separably locked. The soul nail according to the present invention is a collet for soil nails, characterized in that the thrust receiving portion and the thrust applying portion are formed by saw-toothed annular protrusions that mesh with each other. The soul nail according to the present invention is the first
Each member constituting the collet is provided with a connecting portion which is detachably engaged with the second collet and is broken by the thrust force when the soil nail is driven. Further, a soil nail driving device according to the present invention is a soil nail driving device for driving a soil nail into the ground, in which the soil nail is slidably loaded together with a separable collet, and the collet is used. And a compressed air supply source for supplying compressed air into the cylinder in order to apply thrust to the head of the soil nail.
Further, the soil nail driving device according to the present invention is characterized in that a cover for preventing the collet from popping out is provided at the tip of the cylinder. Further, the soil nail driving device according to the present invention is characterized in that a disassembly projection for disassembling the collet is provided on the inner surface of the cover.

In the present invention, the collet is detachably attached to the head of the soil nail, and the thrust is transmitted to the head by the thrust applying portion. The soil nail driving device includes a cylinder into which the soil nail is loaded together with the collet, and applies thrust to the collet by supplying compressed air. Therefore, the soil nail advances together with the collet, jumps out through the cover, and is driven into the ground. On the other hand, the collet collides with the disassembly projection provided on the inner surface of the cover to disassemble and remains in the cover.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. 1 is a sectional view of a soil nail driving apparatus according to an embodiment of the present invention in a state in which a drain nail is loaded, FIG. 2 is a front view of a collet, FIG. 3 is a rear view of the collet, and FIG. FIG. 5 is a cross-sectional view showing a connecting structure of members constituting the collet, FIG. 5 is a cross-sectional view taken along line VV of FIG. 1, and FIG. 6 is a view showing a state in which a drain nail is driven into a slope. In FIG. 6, 1 is a soft ground having a slope 1a which is an object of ground improvement, 2 is a drain nail driven into the slope 1a for strengthening the slope and removing permeated water, 3 is a drain nail 2 It is a soil nail driving device for driving the surface 1a.

1 and 5, the drain nail 2 is shown.
Is composed of a head portion 2A, a drainage portion 2B joined to the rear end side of the head portion 2A with their axes aligned, and a collet 21, which will be described later, mounted on the head portion 2A at the time of driving. The total length of the drain nail 2 is about 8 m or less, the length of the head 2A is about 1 m, and the length of the drainage unit 2B is about 7 m. The head portion 2A is made of a metal such as iron or a synthetic resin and is formed of a rod-shaped body having a sharp tip, and a small diameter portion 5 is formed at the center of the rear end surface.
Are integrally projected, and the front end portion of the drainage portion 2B is fitted into the small diameter portion 5 and joined by welding or the like.
On the other hand, a thrust receiving portion 7 is provided on the peripheral surface near the front end of the head 2A. Since the thrust receiving portion 7 is formed in a sawtooth shape, the thrust receiving portion 7 is composed of a plurality of annular convex portions 7a and grooves 7b arranged in parallel in the axial direction of the head 2A, and the peripheral surface of the convex portion 7a is required forward. It is inclined at an angle, and the rear surface is orthogonal to the axis of the head 2A.

The drain portion 2B has a plurality of rings 10 having the same outer diameter and arranged at a predetermined interval in the axial direction of the drain nail 2, and a predetermined circumferential interval on the outer peripheral surface of the rings 10. A plurality of shaft core materials 1 arranged at intervals
And 1 form a lattice-like tubular body. The opening 12 of the drainage portion 2B, that is, the space portion between the ring 10 and the shaft core 11 enables drainage of the permeated water 13 (see FIG. 6) in the ground 1. The opening ratio of the drainage portion 2B is approximately a / (a +) where a is the distance between the shaft core members 11 and b is the outer diameter of the shaft core members 11.
given in b).

As the material of the ring 10 and the shaft core material 11,
Since the drainage portion 2B is pulled by the head portion 2A and driven into the ground when the drain nail 2 is driven, a material having sufficient material strength to withstand the tensile force is selected. To satisfy this, it is made of a metal such as iron, but is not limited to this, and may be made of synthetic resin as long as it has high strength. When both the ring 10 and the mandrel 11 are made of metal, they are joined to each other by welding or the like, and when they are made of synthetic resin, they are joined by welding or adhesion. As the shaft core material 11,
In the present embodiment, an example of using a reinforcing bar having a circular cross-sectional shape is shown, but the present invention is not limited to this, and may have an appropriate cross-sectional shape such as a triangle, a quadrangle, or a trapezoid.

1 to 3, the collet 21 is shown.
Is composed of a cylindrical first collet 23 that is detachably attached to the head portion 2A of the soil nail 2, and a cylindrical second collet 24 located behind the first collet 23. The first collet 23 is composed of two members 23 </ b> A that are split into a semi-cylindrical shape and are separably coupled. A thrust applying portion 27 that applies a thrust to the soil nail 2 is provided on the inner peripheral surface of each member 23A. The thrust applying portion 27 is formed in a sawtooth shape, and is composed of a plurality of annular convex portions 27a and grooves 27b which mesh with the thrust receiving portion 7 formed on the head portion 2A of the soil nail 2. The convex portion 27a has a vertical surface that is orthogonal to the axis of the first collet 23 and that abuts on the rear surface of the convex portion 7a of the thrust receiving portion 7, and an inclined peripheral surface that abuts the slope of the convex portion 7a. There is. Further, as shown in FIG. 4, engaging pieces 28 that engage with each other are provided on the inner side surfaces of the members 23A that face each other in parallel.
And a hook-shaped engaging recess 29 are provided, and the two members 23A are separably coupled by the engagement thereof.
Two engaging pieces 28 and two engaging recesses 29 are provided near the front end and near the rear end of the member 23A. Further, when the two members 23A are joined by the engagement of the engagement piece 28 and the engagement recess 29 on the front surface of each member 23A,
The convex portions 30 facing each other are integrally provided so as to project forward. The convex portion 30 is formed of a trapezoidal convex portion and is for opening and disassembling the two members 23A by coming into contact with a disassembly projection 31 to be described later when the drain nail 2 is fired. The inner surface is formed as a slope 30a. As such a convex portion 30, the front end portion of the member 23A may have a semi-conical shape, and the semi-conical portion may have a convex portion. Further, the engagement piece 28 has a strength such that it can be damaged when the two members 23A are opened.

Further, a pair of connecting portions 35 are integrally provided on the back surface of each member 23A so as to project rearward. The tip portion 35a of the connecting portion 35 is engaged with the engagement hole 36 formed in the second collet 24 while preventing the slip-out, and thus the soil nail driving device 3 is installed downward. This prevents the soil nail 2 and the collet 21 from descending due to their own weight. Tip part 35 of connecting part 35
Although a is a strength that can sufficiently withstand the weight of the drain nail 2, the strength a is such that it can be easily broken by the thrust applied to the first collet 23 at the time of driving. Not only the tip portion 35a but also the connecting portion 35
It is also possible to form an appropriate portion in a narrow width or to provide a notch and use this portion as a breaking portion.

The second collet 24 has a cylindrical body 24a through which the head portion 2A of the drain nail 2 slidably passes.
And the engaging hole 3 provided integrally on the front end side of the main body 24a.
6 and a flange 24b having 6 The engagement hole 36 is formed in a keyhole shape so that the distal end portion 35a can be inserted and locked, so that the distal end portion 35a of the connecting portion 35 can be inserted into the round hole portion. Three
6a and a long hole portion 36b for locking the tip portion 35a.

Such first and second collets 23, 24
The collet 21 made of is attached to the head 2A of the drain nail 2 in advance when the drain nail 2 is driven. At the time of mounting, after the second collet 24 is fitted on the head portion 2A, the thrust receiving portion 7 and the thrust applying portion 27 are formed by the engagement of the engaging piece 28 and the engaging recess 29.
The two members 23A are coupled so that and engage with each other, and the head 2A is sandwiched therebetween.
It suffices to insert a into the round hole portion 36a of the engagement hole 36 of the flange 24b and rotate the first collet 23 or the second collet 24 by a small angle to engage the tip portion 35a with the long hole portion 36b.

The soil nail driving device 3 used for driving the drain nail 2 having the above structure into the ground.
Is a cylinder 40 into which the drain nail 2 is loaded together with the collet 21, a cover 41 integrally provided at the front end opening of the cylinder 40, a back plate 42 provided at an intermediate portion of the cylinder 40, and a cylinder 40 inside the cylinder 40. It is generally configured by a compressed air supply source 44 or the like that supplies high-pressure compressed air 43. Compressed air 43 is provided on the circumferential surface of the cylinder 40.
Has an inlet 46 formed therein, and the inlet 46 is connected to the compressed air supply source 44 by a pipe 47. The cover 41 is formed in a tubular body having a diameter larger than that of the cylinder 40, and a firing port 48 having a size through which the drain nail 2 can pass is formed on the front surface. Further, the projecting port 48 is provided with the disassembling projection 31 that disassembles the first collet 23 when the drain nail 2 is projected, toward the inside of the cover 41. The disassembling projection 31 is formed of a tubular body, and the slope 30a of the convex portion 30 collides with the inner opening end surface thereof. Further, a plurality of air holes 49 are formed on the peripheral surface of the cover 41.

The back plate 42 constitutes a reaction body when the drain nail 2 is fired, and is constituted by two members 42a which face each other in the radial direction of the cylinder 40 and whose opposing surfaces are formed in an arc shape. After the drain nail 2 is mounted, the main body 24a is held by being inserted into the cylinder through an opening 40a provided on the peripheral surface of the cylinder 40 by an opening / closing device (not shown).

In the soil nail driving device 3 having such a structure, when driving the drain nail 2,
The drain nail 2 with the collet 21 attached to the cylinder 4
0 from the rear end opening, and then the back plate 42 is inserted into the cylinder 40 to insert the main body 24 of the second collet 24.
Hold a. After that, the drain nail driving device 3 is set at an appropriate interval with respect to the slope 1a. FIG. 1 shows this state. Next, the compressed air 43 is supplied from the compressed air supply source 44 into the cylinder 40 (for example, 50 to 200 kg).
/ Cm ² ) is instantly introduced to apply thrust to the first collet 23. When thrust is applied to the first collet 23, the tip end portion 35a of the connecting portion 35 is broken and the first collet 23 and the second collet 23
The collet 24 separates. Therefore, the first collet 2
3 advances in the cylinder 40, and the thrust applying unit 27 moves the head 2
The thrust receiving portion 7 of A is pressed from the rear to transmit the thrust. Therefore, the drain nail 2 moves forward in the cylinder 40 integrally with the first collet 23, and at the time of jumping out of the cylinder 40, a sufficient thrust force (100 to 300 Km /
h) is given. The first collet 23 is the cylinder 4
0 and the inside of the cover 41 are advanced, and the protrusion 30 collides with the disassembly projection 31 of the cover 41, the first collet 23 is opened and disassembled and remains in the cover 41. That is, the first collet 23 moves forward, and the slope 30a of the convex portion 30 causes the disassembly projection 3
When it collides with No. 1, a component force in the direction of separating each member 23A is generated. Therefore, the engagement piece 28 is damaged and the member 23A is separated from the head 2A of the soil nail 2.
On the other hand, the drain nail 2 is ejected from the firing port 48 of the cover 41 by the thrust provided by the first collet 23 and is driven into the slope 1a. The driving depth of the drain nail 2 is determined by adjusting the pressure of the compressed air 43. The rear end portion of the drainage portion 2B projects from the slope 1a to enable drainage as shown in FIG.

In the soil nail driving device 3 having such a structure, since the thrust is applied to the head 2A of the drain nail 2, the drain portion 2B of the drain nail 2 has the head 2A. As a result of forward movement, only a tensile force is received and no compressive force is received. Therefore, it is not necessary to consider the buckling strength, and a large thrust can be applied. Further, if the buckling strength is not required, the restriction on the material of the drain nail 2 is released, so that the degree of freedom in design is expanded.
Further, the structure of the soil nail driving device 3 itself is simple and can be manufactured at low cost.

The collet 21 mounted on the head 2A of the drain nail 2 is composed of a first collet 23 and a second collet 24. The first collet 23 is composed of a plurality of members 23A. Engaging piece 28 and engaging recess 2
Since the thrust applying portion 27 provided on the inner surface of each member 23A by the engagement of 9 is formed by sawtooth projections and grooves, the collet 21 can be easily attached to the head 2A. The thrust can be reliably transmitted to the head 2A. Further, the first collet 23 holds the head 2A and is connected to the second collet 24 so as to be easily disassembled by thrust, and the second collet 24 is fixed to the soil nail driving device 3 side. Therefore, even when the drain nail 2 is driven downward, the head 2A can be locked at a predetermined position in the cylinder 40. Further, since the first collet 23 does not jump out of the cover 41 by advancing in the head 2A cylinder 40 and disassembling in the cover 41, the driving work of the drain nail 2 can be safely performed. .

The drain nail 2 includes a head 2A and a drain 2
B and a collet 21 mounted on the head 2A, the collet 21 is composed of first and second collets 23 and 24, and a thrust applying portion 27 of the first collet 23 is provided on the peripheral surface of the head 2A. Since the thrust receiving portion 7 that meshes is provided, when the thrust is transmitted from the first collet 23, the thrust receiving portion 7 jumps out of the soil nail driving device 3 and is reliably driven into the ground.

In the above embodiment, the case of driving the drain nail 2 having a reinforcing function and a draining function has been described, but the present invention is not limited to this and has only a reinforcing function. It can also be applied to soil nails.

[0024]

As described above, the collet for soil nails according to the present invention comprises the first collet mounted on the head of the soil nail and the second collet located behind the first collet, The first collet is composed of a plurality of members provided with a thrust applying section for transmitting a thrust to the head and disassembledly coupled, and the second collet is a tubular body through which the head slidably passes. Since each member is provided with a connecting portion which is detachably engaged with the second collet and is broken by the thrust when the nail nail is driven, it is easy and easy for the head. Can be attached to. In addition, since the thrust applying portion is formed by the saw-toothed protrusion and the groove, the thrust can be reliably transmitted to the head. The first collet is connected to the second collet so that it can be easily disassembled by thrust, and the second collet is fixed to the soil nail driving device side to lock the first collet. Even when the soil nail is driven downward, the head and the collet can be loaded at predetermined positions in the cylinder. Furthermore, the first collet does not jump out of the cover by advancing in the cylinder and disassembling in the cover, so that the nail nail can be driven in safely.

The soil nail according to the present invention has a head portion having a conical tip portion and a thrust receiving portion provided on the peripheral surface thereof, a drainage portion continuously provided at the rear portion of the head portion, and a detachable portion on the head portion. A collet that is freely mounted and is loaded into the soil nail driving device together with the head when driving, and a thrust applying section that engages the collet with the thrust receiving section and transmits thrust to the head is provided. First composed of a plurality of members that are connected to each other and can be disassembled
Since it is composed of a collet and a second collet which is formed in a tubular body through which the head slidably penetrates and is fixed in the rear end portion of the soil nail driving device and which locks the first collet in a separable manner, Since the structure is simple and it is driven by the front driving method, it receives only the pulling force by the forward movement of the head and does not receive the compressive force at all, therefore the buckling strength is not required and the material selection of the nail itself is selected. And the degree of freedom in design is expanded.

A soil nail driving apparatus according to the present invention comprises a cylinder into which a soil nail is slidably loaded together with a separable collet, and a cylinder inside the cylinder for applying thrust to the head through the collet. Since it has a compressed air supply source for supplying compressed air, it can be manufactured with a simple structure and at a low cost, and can be driven by giving a predetermined thrust to the head of the soil nail. Further, since the cover for preventing the collet from popping out is provided at the tip of the cylinder, the driving operation can be performed safely. Further, since the disassembly projection for disassembling the first collet is provided on the inner surface of the cover, the first collet can be reliably separated from the head of the soil nail.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a soil nail driving apparatus according to the present invention in a state in which a drain nail is loaded.

FIG. 2 is a front view of a collet.

FIG. 3 is a rear view of the collet.

FIG. 4 is a cross-sectional view showing a connecting structure of members forming a first collet.

5 is a sectional view taken along line VV of FIG.

FIG. 6 is a view showing a state where a drain nail is driven into a slope.

[Explanation of symbols]

1 ... Ground, 1a ... Slope, 2 ... Drain nail, 2A ... Head part, 2B ... Drainage part, 3 ... Soil nail driving device, 7 ... Thrust receiving part, 10 ... Ring, 11 ... Shaft core material, 21 ... Collet, 23 ... First collet, 23A ... Member, 24 ... Second collet, 27 ... Thrust applying section, 28 ... Engaging piece, 29 ... Engaging concave section, 30 ... Convex section, 31 ... Disassembly projection, 35 ... Connection Department,
36 ... Engagement hole, 40 ... Cylinder, 41 ... Cover, 44 ...
Compressed air source.

Claims (10)

[Claims] 1. A thrust imparting means for transmitting a thrust force to the head, comprising a first collet mounted on the head of a soil nail and a second collet located behind the first collet. A plurality of members that are provided with a portion and are disassembledly coupled to each other, the second collet is a tubular body through which the head slidably passes, and
A collet for soil nails, comprising a connecting portion which is detachably engaged with the collet and is broken by thrust when the soil nail is driven. 2. The soil nail collet according to claim 1, wherein the thrust transmitting portion is constituted by a serrated annular projection. 3. The collet for soil nails according to claim 1 or 2, wherein a projection for disassembling the first collet by contacting a disassembly projection provided on the driving device side is provided on the front surface of the first collet. Collet for soil nails characterized by being provided. 4. The soil nail collet according to claim 1, 2, or 3, wherein a plurality of members constituting the first collet are detachably coupled by engagement of an engagement piece and an engagement recess. Collet for soil nails. 5. A head portion having a conical tip portion and a thrust receiving portion provided on the peripheral surface thereof, and a drain portion connected to a rear portion of the head portion.
A collet that is detachably attached to the head and is loaded into the soil nail driving device together with the head at the time of driving, and the collet is engaged with the thrust receiving portion to transmit the thrust to the head. A first collet, which is provided with a thrust applying portion and is composed of a plurality of members that can be disassembled, and a cylindrical body through which the head slidably penetrates. The first collet is fixed in a soil nail driving device. Second to lock the collet separably
A soil nail that is composed of a collet and a collet. 6. The soil nail according to claim 5, wherein
A soil nail characterized in that the thrust receiving portion and the thrust applying portion are formed by saw-toothed annular projections that mesh with each other. 7. The soil nail according to claim 5 or 6, wherein each member constituting the first collet is detachably engaged with the second collet and is ruptured by a thrust force when the soil nail is driven. Soil nail which is characterized by having. 8. A soil nail driving device for driving a soil nail into the ground, wherein a cylinder into which the soil nail is slidably loaded together with a separable collet, and a head of the soil nail via the collet. A soil nail driving device comprising: a compressed air supply source for supplying compressed air into the cylinder in order to apply thrust. 9. The soil nail driving device according to claim 8, wherein a cover for preventing the collet from popping out is provided at the tip of the cylinder. 10. The soil nail driving device according to claim 9, wherein a disassembly projection for disassembling the collet is provided on the inner surface of the cover.