JP6486793B2 - Rock bolt and its construction method - Google Patents

Description

  The present invention relates to a rock bolt and a construction method thereof.

  Generally, a mountain tunnel employs a NATM method as shown in FIG. 20 (a) and a sheet pile method as shown in FIG. 20 (b). In recent years, the NATM construction method has been adopted as a standard construction method for tunnels. In the NATM construction tunnel, as shown in FIG. 20 (a), spray concrete 90 is applied to the excavation wall surface as a primary lining, and a rock bolt 91 is placed on a natural ground. In addition, a lining concrete 100 is placed and constructed inside the shotcrete 90 with a waterproof sheet and a cushioning material interposed therebetween. On the other hand, the sheet pile method is older than the NATM method, but as shown in FIG. 20 (b), it is supported by a sheet pile 92 and a supporting work 93 so that the wall surface of the mine immediately after excavation does not collapse, and the inner side is covered. The construction concrete 100 is constructed. In particular, railway tunnels have a long history, and many tunnels built using the sheet pile method are still in service.

  Although the structure of the tunnel constructed by the sheet pile method is stable, it is necessary to lay equipment necessary for operation in the tunnel, especially for the safe and stable transportation of railways, and even part of the structure It is necessary to repair or reinforce partial deterioration. Therefore, it is necessary to attach a fixed object such as a reinforcing member to the inner surface of the lining concrete. This need is the same for NATM tunnels over the years.

  Therefore, normally, as shown in FIG. 21, an anchor 94 is driven and a fixed object is attached. This will be described in more detail as follows. First, as shown in FIG. 21 (a), a cylindrical diameter-expanding member 94a whose one end is capable of expanding, and a taper bolt 94b whose one end is formed with a male screw and the other end is formed in a tip cone shape. An anchor 94 is prepared and inserted into a drilling hole 110 formed in the lining concrete 100. Then, as shown in FIG. 21 (b), when the anchor 94 is inserted into the drilling hole 110 and the diameter-expanding member 94a is struck into the hole back side using a not shown driving rod, hammer or the like, the taper bolt 94b The tip cone-shaped portion enters the diameter-expanding member 94a and pushes one end portion apart. Thereby, the diameter-expanding member 94 a comes into close contact with the inner wall surface of the drilling hole, and the anchor 94 is fixed to the lining 100. Subsequently, a fixed object 96 such as a reinforcing member is engaged with the male screw of the taper bolt 94 b protruding from the hole 110, and a washer 97 and a nut 98 are attached to the male screw protruding from the fixed object 96. Then, when the nut 98 is tightened, the anchor 94 is completed as shown in FIG. Moreover, the method of patent document 1 is also proposed as a method of attaching to an older deteriorated lining or the like.

Japanese Patent Laid-Open No. 2002-21498

  However, the attachment of the fixed object 96 by the anchor 94 has the following problems particularly in the case of a railway tunnel. That is, in a railway tunnel, a positive pressure is generated at the head of a train passing at a high speed, while a negative pressure is generated at the rear. Therefore, a fixed object attached to the inner surface of the lining concrete 100 and an anchor 94 that supports the fixed object, and thus In the lining concrete 100, as shown in FIG. 21C, in addition to the dead weight F2 of the fixed object 96, a dynamic load due to passing through the train acts, and a shearing force F3 acts on the lining concrete 100. There is also.

  An attachment structure having a sufficient safety factor, that is, a larger diameter and deep anchor may be adopted so that the fixed object 96 never falls off even when the force F3 is repeatedly applied. Then, the compressive stress F1 acting on the lining concrete 100 is also increased by the expansion of the anchor itself, which inevitably poses a burden on the lining that has passed through the years, thereby reducing the tunnel life and the complexity of maintenance. It is difficult to predict what kind of impact will occur. Further, even with the anchor according to Patent Document 1, although the load on the lining by the anchor placement itself is reduced, it is inevitable that the shearing force F3 acts on the lining.

  The present invention has been made to solve the above-described problems, and can fix a fixed object without applying an extra load to the lining, and can also reinforce a natural ground in which the lining is placed. It aims at providing a rock bolt and its construction method.

  The lock bolt according to the present invention is formed in a cylindrical shape and has an internal space extending in the axial direction, and an inflatable tube that expands by plastic deformation by injecting a pressurized fluid into the internal space, and the expansion A constraining member that is inserted into a pipe and is disposed in a position corresponding to at least the lining in the drilling hole and has a diameter-enlarging slit that is formed in a cylindrical shape and extends in the axial direction at the tip, and the expansion A screw portion that is attached to an end portion of the type pipe and that can be engaged with the fixed object when fixing to the hole.

  According to this configuration, in the inflatable pipe, since the cylindrical restraining member is arranged in the portion arranged in the lining, even if the inflatable pipe expands, the portion arranged in the lining The expansion is restricted by the restraining member. On the other hand, since the diameter-enlarging slit extending in the axial direction is provided at the distal end portion of the restraining member, the inflatable tube on the distal end side from the restraining member can be inflated smoothly. Therefore, the rock bolt can be fixed to the natural ground in a state in which the load is prevented from acting on the lining by the expansion of the inflatable pipe, and at the same time, the natural ground can be reinforced by the lock bolt. In addition, since the screw portion 2 is attached to the rear end portion of the inflatable tube 1, the fixed object 8 can be reliably engaged with the screw portion 2 protruding from the drilling hole by screw fastening with good workability.

  In the lock bolt, the screw portion may be a male screw that protrudes from the hole when the inflatable pipe is fixed to the hole. Thereby, for example, it is possible to attach a fixed object to the lining firmly by attaching a washer or nut to the male screw and tightening it.

  In each of the above lock bolts, the restraining member is provided with a plurality of slits for expanding the diameter, and the plurality of slits for expanding the diameter are expanded between the back surface of the lining and the natural ground with the expansion of the inflatable pipe. It can be configured to be possible.

  According to this configuration, since the inflatable pipe is expanded in diameter by the plurality of slits provided at the distal end portion of the restraining member between the back surface of the lining and the natural ground, a load on the lining is generated. In addition, the inflatable portion of the inflatable tube is securely fixed to the natural ground, so that the effect of reinforcing the natural ground as a lock bolt can be used more effectively in addition to the attachment of a fixed object.

  In the lock bolt, the restraining member may have at least a length that reaches from the lining to the ground.

In the lock bolt, a predetermined length from the tip of the lock bolt can be fixed to the ground by a cement fixing material.

  The rock bolt construction method according to the present invention includes a step of forming a hole for the ground and the lining applied to the surface thereof, and a step of inserting the lock bolt according to any one of the above-described methods into the hole. And inflating by injecting a pressurized fluid into the internal space of the inflatable pipe, thereby bringing the inflatable pipe into close contact with the inner wall surface of the drilling hole. A step of constraining expansion of a portion disposed therein by the constraining member, a step of expanding a diameter of a distal end portion of the constraining member with expansion of the inflatable tube, and a step of engaging a fixed object with the screw portion And attaching a nut and a washer to the screw part, sandwiching the fixed object between the washer and a surface of the lining, and tightening the nut to the screw part, , And a, a step of pressing the surface of the lining through the washer and nut.

  In the construction method of the lock bolt, the screw portion is a male screw protruding from the drilling hole when the inflatable pipe is fixed to the drilling hole, and the fixed object is a male screw protruding from the drilling hole. It can be engaged with a screw.

  In the construction method of each of the lock bolts, prior to the insertion of the lock bolt into the drilling hole, or together with the insertion of the lock bolt, placing a cement fixing material at the back end of the drilling hole; and And fixing the predetermined length of the lock bolt to the drilling hole by the cement fixing material.

  According to the present invention, the lock bolt is fixed to the ground in a state in which a load is prevented from acting on the lining, and a fixed object can be securely attached to the screw portion of the lock bolt. You can also reinforce natural ground.

It is sectional drawing of the tunnel in which the rock bolt concerning this invention is constructed. It is sectional drawing of the rock bolt which concerns on one Embodiment of this invention. It is a side view of the inflatable pipe | tube which comprises the lock bolt of FIG. It is a perspective view explaining the preparation procedure of the pipe | tube main body of the inflatable pipe | tube of FIG. It is the side view (a) and AA sectional view (b) of a restraint member. It is sectional drawing which shows the construction method of the rock bolt of FIG. It is sectional drawing which shows the construction method of the rock bolt of FIG. It is sectional drawing which shows the construction method of the rock bolt of FIG. It is sectional drawing which shows the construction method of the rock bolt of FIG. It is sectional drawing which shows the construction method of the rock bolt of FIG. It is sectional drawing which shows the construction method of the rock bolt of FIG. It is sectional drawing which shows the construction method of the rock bolt of FIG. It is sectional drawing which shows the construction method of the rock bolt of FIG. It is sectional drawing which shows the construction method of the rock bolt of FIG. It is sectional drawing which shows the construction method of the rock bolt of FIG. It is sectional drawing which shows the construction method of the rock bolt of FIG. It is sectional drawing which shows the other example of the lock bolt which concerns on this invention. It is sectional drawing which shows the other construction method of the lock bolt which concerns on this invention. It is sectional drawing which shows the other construction method of the lock bolt which concerns on this invention. It is a figure explaining a prior art. It is a figure explaining a prior art.

  Hereinafter, an embodiment of a rock bolt and a construction method thereof according to the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of a tunnel in which a rock bolt according to this embodiment is constructed. In the following, for convenience of explanation, the rear end side of the drilling hole into which the lock bolt is inserted is “front end side” or “leading side”, and the opposite side is “base end side” or “rear end side” May be called. In addition, the direction in which the hole is extended and the direction in which the corresponding lock bolt extends may be referred to as an axial direction. Further, the direction may be indicated by the wording of the radial direction or the circumferential direction around the axial direction.

  As shown in FIG. 1, a sheet pile (not shown) is attached to the surface of a natural ground 300 on the inner wall surface X of this tunnel, and lining concrete (hereinafter simply referred to as lining) 100 is placed on the surface. The rock bolt 10 according to the present embodiment is applied to a drilling hole that penetrates the lining 100 and the lining back space 200 arranged by the sheet pile and extends to the natural ground. In addition, after the construction of the lock bolt 10, a fixed object 8 such as a reinforcing plate is attached to the surface of the lining. Below, the structure of a lock bolt is demonstrated first, and the construction method is demonstrated after that.

<1. Structure of rock bolt>
FIG. 2 is a side view of the lock bolt according to the present embodiment. As shown in the figure, the lock bolt 10 according to the present embodiment is formed integrally with an inflatable tube 1 formed in a long shape by a steel pipe (tube member) and a rear end portion of the inflatable tube 1. And a cylindrical restraining member 3 into which the inflatable tube 1 is inserted. Hereinafter, these members will be described in detail.

<1-1 Inflatable tube>
FIG. 3 is a side view of the inflatable tube. As shown in FIG. 1, the inflatable tube 1 includes a tube body 11, a tip sleeve 12 attached to the tip of the tube body 11, and a mouth sleeve 13 attached to the rear end of the tube body 11. Further, the above-described screw portion 2 is integrally attached to the rear end portion of the mouth sleeve 13. First, a method for producing the tube body 11 will be described.

  FIG. 4 is a perspective view for explaining the manufacturing procedure of the tube body. First, as shown in FIG. 4 (a), a hollow cylindrical steel pipe 100 having an internal space 101 is prepared, and after pressing it into a plate shape, as shown in FIG. The inflatable tube 10 having a C-shaped cross section is formed so as to have a concave portion 102 that is bent in a cylindrical shape with the direction as an axial direction and extends in the axial direction. The steel pipe 100 has a thickness of about 2 to 3 mm so as to be deformed by the pressure of water supplied to the internal space 101 as will be described later. Moreover, it is preferable to make it plate shape so that the steel pipe 100 may not be crushed completely so that a fluid can flow into the internal space 101 of the steel pipe 100.

  Returning to FIG. 3, the description of the inflatable tube 1 will be continued. As shown in the figure, the tip sleeve 12 attached to the tip of the inflatable tube 1 is formed in a hollow cylindrical shape with the tip closed, and the tip of the tube body 11 is inserted and fixed by welding or the like. At the same time, the tip of the tube body 11 is sealed. The mouth sleeve 13 attached to the rear end portion of the tube main body 11 is formed in a cylindrical shape, and the front end side is open. The rear end portion of the tube main body 11 is inserted into the front end opening of the mouth sleeve 13 and is fixed by welding or the like. On the other hand, the screw portion 2 described above is integrally connected to the rear end portion of the mouth sleeve 13. The threaded portion 2 is formed with a male screw, and is formed with a through hole 21 communicating with the internal space 101 of the tube body 11 along the axial direction. At this time, the outer peripheral surface and the concave portion 102 are closed by welding at the rear end portion of the tube main body 11 so that only the opening to the internal space 101 communicates with the through hole 21 of the screw portion 2.

<1-2 Restraint member>
Next, the restraining member 3 will be described. FIG. 5 is a side view of the restraining member (a) and a cross-sectional view along line AA (b). As shown in the figure, the restraining member 3 is formed in a hollow cylindrical shape having an open front end and a rear end, and has an inner diameter such that the tube body 11 of the inflatable tube 1 can be inserted. However, the inner diameter of the restraining member 3 is smaller than the outer diameter of the mouth sleeve 13. Therefore, as described later, the restraining member 3 is inserted into the drilling hole 400 while being pushed by the mouth sleeve 13.

  In addition, a plurality of diameter-enlarging slits 31 are formed on the outer peripheral surface on the distal end side of the restraining member 3. These diameter-expansion slits 31 are formed at equal intervals in the circumferential direction (four locations in this embodiment) and extend in the axial direction. Each of the diameter-enlarging slits 31 extends to the tip of the restraining member 3 and is open to the outside. And this restraining member 3 is arrange | positioned with respect to the inflatable pipe | tube 1 from the opening sleeve 13, and when the inflatable pipe | tube 1 is arrange | positioned in a drilling hole, while being arrange | positioned in the lining 100, diameter expansion is carried out. The front end where the slits 31 are formed is formed in such a length as to enter the lining back space 200 arranged by the sheet pile between the lining back and the ground.

<2. Rock bolt installation method>
Next, a construction method of the lock bolt configured as described above will be described with reference to FIGS. In this embodiment, as shown in FIG. 1, a plurality of lock bolts are driven at predetermined intervals along an inner wall surface X on which a sheet pile and lining 100 are driven, targeting an existing tunnel 500. First, with a known drilling machine 6 as shown in FIG. 6, a drilling hole 400 that penetrates the lining 100 and the lining back space 200 and extends to the natural ground 300 is formed. Next, as shown in FIG. 7, the thickness of the lining 100 is measured with a scale 150, and it is confirmed that the slit 31 for expanding the diameter of the lock bolt to be placed later is located closer to the ground than the back of the lining 100. Keep it.
In addition, the lining back space 200 does not necessarily exist between the lining 100 and the ground 300, and the lining back space 200 is filled with an injection material in addition to a sheet pile. Or it will be filled by future tunnels, etc.

In parallel with this, the fixing material is prepared. That is, as shown in FIG. 8, a water-absorbing bag body 7 containing a cement mortar 7a is prepared. The bag body 7 is provided with a reinforcing mesh 7b for shape retention on the surface. And after soaking this bag body 7 in water for a predetermined time, as shown in FIG. 9, the bag body 7 is arrange | positioned in the back end part of the drilling hole 400. As shown in FIG. Following this, the inflatable tube 1 to which the restraining member 3 is attached is inserted into the drilling hole 400. At this time, an adhesive is applied to the surface of the restraining member 3.

  Then, the inflatable tube 1 is inserted into the drilling hole 400 while pushing the restraining member 3 by the mouth sleeve 13, and the mouth sleeve 13 and the restraining member 3 are arranged in the lining 100 as shown in FIG. 10. At this time, it arrange | positions so that the front end side of the restraint member 3, ie, the part in which the slit 31 for diameter-expansion is formed may protrude in the lining back space 200 from the lining 100. At this time, the restraining member 3 is fixed in the lining 100 with an adhesive. On the other hand, as shown in FIG. 11, the screw portion 2 protrudes outside from the drilling hole 400, but a gap L is formed between the rear end of the mouth sleeve 13 and the opening of the drilling hole 400. Keep it. Accordingly, the rear end of the mouth sleeve 13 is prevented from protruding from the hole 400 even when the mouth sleeve 13 is pushed out to the hole opening side due to the expansion of the inflatable tube 1.

  Further, when the inflatable tube 1 is inserted into the drilling hole 400, the bag body 7 disposed at the inner end of the drilling hole 400 is crushed by the inflatable tube 1, and the fixing material flows out into the drilling hole 400 (see FIG. 14). The fixing material also enters a crack or the like in the drilling hole, and temporarily fixes the tip of the inflatable tube 1 to the ground. Subsequently, as shown in FIG. 12, a water injection adapter is connected to the screw portion 2 to connect the water injection hose 61, and pressurized water is supplied to the internal space 101 of the pipe body 11 through the through hole 21 of the screw portion 2. . Thereby, the injected pressurized water is distributed in the inflatable tube 1 and the internal pressure of the internal space 101 is increased. As a result, the inflatable tube 1 expands and expands from the state shown in FIG. 13A to the state shown in FIG. That is, when the pressurized water is injected into the internal space 101 of the inflatable tube 1, the inflatable tube 1 expands in the radial direction and comes into close contact with the inner wall surface X of the drilling hole 400.

  At this time, as shown in FIG. 14, the portion of the inflatable tube 1 that is inside the lining 100 is covered with the restraining member 3, so that the expansion is restricted. On the other hand, since the portion arranged in the lining back space 200 is covered with the portion where the diameter-enlarging slit 31 is formed in the restraining member 3, the inflatable tube 1 is inflated and restrained accordingly. The end of the member 3 sandwiched by the diameter-enlarging slits 31 expands outward in the radial direction, and the diameter is increased. Subsequently, as shown in FIG. 15, the fixed object 8 such as a reinforcing member in which the through hole 81 is formed is engaged with the screw portion 2 protruding from the hole 400. That is, the screw part 2 is inserted into the through hole 81 of the fixed object 8 and the fixed object 8 is brought into contact with the surface of the lining 100. Subsequently, the through hole of the washer 5 is inserted into the screw part 2 protruding from the through hole 81 of the fixed object 8, and the nut 9 is screwed into the screw part 2 and tightened. At this time, the nut 9 is preferably a nut having a locking function. Thus, the fixed object 8 is sandwiched between the washer 5 of the inflatable tube 1 and the surface of the lining 100 by screw tightening using the nut and washer, and the fixed object 8 is pressed against the surface of the lining 100. Thus, the construction of the lock bolt 10 is completed, and the fixed object 8 is fixed to the surface of the lining while reinforcing the natural ground 300. That is, the fixed object 8 can be easily and securely attached to the lining 100 by tightening the nut 9 via the washer 5 to the inflatable pipe 1 fixed to the ground 300 reinforced by the lock bolt 10. .

<3. Features>
As described above, according to the present embodiment, in the inflatable tube 1, the tubular restraining member 3 is disposed in the portion disposed in the lining 100. In addition, the expansion of the portion disposed in the lining 100 is restricted by the restraining member 3. On the other hand, since the diameter-enlarging slit 31 extending in the axial direction is provided at the distal end portion of the restraining member 3, the expansion of the inflatable tube 1 causes the inflatable tube 1 on the distal end side of the restraining member 3 to be smooth. Can expand. Therefore, the lock bolt 10 is fixed to the natural ground in a state in which the load is prevented from acting on the lining by the expansion of the inflatable pipe, and at the same time, the natural ground can be reinforced by the lock bolt 10. In addition, since the screw portion 2 is attached to the rear end portion of the inflatable tube 1, the fixed object 8 is securely fixed to the lining 100 with good workability by screw fastening to the screw portion 2 protruding from the drilling hole 400. Can do.

  Further, in the restraining member 3, a plurality of diameter-expansion slits 31 are formed in a portion protruding from the lining 100 into the lining back space 200, and the diameter is increased between the back surface of the lining 100 and the natural ground 300. It is possible. Therefore, the expandable tube 1 is expanded by the plurality of slits 31 provided at the distal end portion of the restraining member 3 between the back surface of the lining 100 and the natural ground 300, so that the expandable tube 1 is expanded. The tube main body 11 is securely fixed to the ground by friction, and the ground reinforcement effect as the lock bolt 10 can be used more effectively in addition to the attachment of the fixed object 8.

<4. Modification>
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. Note that the following modifications can be combined as appropriate.

<4-1>
In the said embodiment, although the thread part 2 of the inflatable pipe | tube 1 is comprised with the external thread, the thread part 2 in which the internal thread was formed may be sufficient. In this case, as shown in FIG. 16, with respect to the screw portion 2, a washer is attached to the surface of the fixed object, and then a bolt 88 is inserted into the washer 5, and the male screw of the bolt 88 is connected to the screw portion 2. Screwed on. Also by this, the fixed object 8 can be attached.

<4-2>
In the said embodiment, although the enlarged diameter part of the restraint member 3 is arrange | positioned in the lining back space 200 which a sheet pile arrange | positions, as shown in FIG. 17, the restraint member 3 is extended and an enlarged diameter part is a natural ground. It may be arranged within 300. Thereby, even if the lining 100 and the natural ground 300 are largely separated and no sheet pile exists in the lining back space 200, the fixing material such as the bag body 7 containing the cement mole 7 a is stored in the space 200. It can arrange | position to the back end part of the drilling hole 400, without dropping off. In addition, the fixing material that has flowed out to the natural ground 300 when the diameter-expanded portion of the restraining member 3 is expanded at the natural ground 300 is dammed up by the constricting member 3 that has been expanded, and flows into the lining back space 200. Therefore, the effect of the fixing material can be maximized.

<4-3>
The construction method according to the above embodiment is an example, and the attachment of each member can be changed as appropriate. For example, construction can be performed in the order shown in FIG. First, as shown in FIG. 18A, the restraining member 3 is arranged in the lining 100, and the fixing material 7 is placed at the back end of the hole 400 using a rod-like or pipe-like insertion jig 600. Deploy. Subsequently, as shown in FIG. 18 (b), the inflatable tube 1 with a male screw is pushed into the natural ground while being inserted into the restraining member 3. As a result, the fixing material 7 in the drilling hole 400 is crushed by the tip of the inflatable tube 1, and the restraining member 3 is pushed by the mouth sleeve 13 and is disposed at an appropriate position in the lining 100. Even in such a method, a lock bolt can be applied in the same manner as in the above embodiment.

<4-4>
Furthermore, as shown in FIG. 19, a water stop plug can be attached to the rear end of the inflatable tube. That is, as shown in FIG. 19A, the water stop plug 800 includes a small-diameter portion 801 formed in a hollow cylindrical shape and a disk-shaped large-diameter portion 802 attached to the rear end thereof. For example, it can be formed of an organic compound such as rubber with little deterioration against water, acid, alkali and the like. The small diameter portion 801 can be inserted into the drilling hole 400 of the lining 100, and the inner diameter substantially matches the outer diameter of the mouth sleeve 13. The large-diameter portion 802 is formed with a through hole 803 through which a male screw can be inserted. Then, as shown in FIG. 19B, after the inflatable tube 1 is inflated, the small diameter portion 801 of the water stop plug 800 is disposed so as to cover the outer periphery of the rear end portion of the mouth sleeve 13. At this time, the male screw 2 passes through the large-diameter portion 802 of the water stop plug 800 and protrudes to the outside. The large-diameter portion 802 contacts the surface of the lining 100 and is pressed by the washer 5 by tightening the nut 9. By using such a water stop plug 800, water leakage from the drilling hole 400 to the surface side of the lining 100 is prevented, and damage to the lining 100 can be further suppressed.

1: Expandable tube 2: Screw part 3: Restraint member 10: Lock bolt

Claims (8)

A lock bolt that is fixed to a drilling hole formed in the ground and the lining applied to the surface thereof, and capable of attaching a fixed object to the surface of the lining,
An inflatable tube that is formed in a cylindrical shape and has an internal space extending in the axial direction, and that expands by plastic deformation by injecting a pressurized fluid into the internal space;
A constraining member inserted into the inflatable pipe and disposed at a position corresponding to at least the lining in the drilling hole, and having a diameter-enlarging slit formed in a cylindrical shape and extending in the axial direction at the distal end portion;
A threaded portion that is attached to an end of the inflatable tube and that can be engaged with the fixed object at the time of fixing to the hole;
Equipped with a rock bolt.   2. The lock bolt according to claim 1, wherein the screw portion is a male screw that protrudes from the hole when the inflatable tube is fixed to the hole.   In the restraining member, a plurality of slits for expanding the diameter are provided, and the plurality of slits for expanding the diameter are configured to be capable of expanding between the back surface of the lining and a natural ground with the expansion of the inflatable pipe. The lock bolt according to claim 1 or 2.   The lock bolt according to claim 1 or 2, wherein the restraining member has at least a length reaching from the lining to the natural ground.   The lock bolt according to any one of claims 1 to 4, wherein a predetermined length from a tip of the lock bolt is fixed to the ground by a cement fixing material. Forming a drilling hole for the ground and the lining applied to the surface;
Inserting the lock bolt according to any one of claims 1 to 4 into the hole;
Injecting a pressurized fluid into the internal space of the inflatable pipe to cause the inflatable pipe to be in close contact with the inner wall surface of the drilling hole, and in the lining in the inflatable pipe Constraining the expansion of the arranged portion by the restraining member, and expanding the diameter of the tip of the restraining member as the inflatable tube is inflated;
Engaging a fixed object with the thread portion;
A nut and a washer are attached to the threaded portion, the fixed object is sandwiched between the washer and the surface of the lining, and the nut is tightened with respect to the threaded part, thereby fixing the fixed object to the washer. And pressing the lining against the surface via a nut;
A construction method of rock bolts. The screw portion is a male screw that protrudes from the hole when the inflatable tube is fixed to the hole.
The lock bolt construction method according to claim 6, wherein the fixed object is engaged with a male screw protruding from the hole. Prior to insertion of the lock bolt into the drilling hole or with the insertion of the lock bolt, placing a cement fixing material at the back end of the drilling hole; and
Fixing the predetermined length of the lock bolt to the drilling hole by the cement fixing material;
The rock bolt construction method according to claim 6 or 7, further comprising:

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