JP2019143404A - Plate for rock bolt, rock bolt installation structure, rock bolt loading test method - Google Patents

Abstract

To provide a plate for a rock bolt that can prevent a waterproof sheet from being damaged by suppressing protrusion of the rock bolt from a placement surface to the maximum, and that enables a rock bolt pull-out test.SOLUTION: A rock bolt plate 1 comprises a nut portion 2 having an internal thread 23 formed on the inside, a substantially flat flange portion 3 that is integrally formed with the nut portion 2 so as to expand outward from a base end portion of the nut portion 2, and on which the protruding side of the nut portion 2 is a bearing surface 31. The length of the internal thread 23 is equal to or longer than the total length of the screwed length of the rock bolt 6 with an external thread 62 to obtain a required pulling strength and the screwed length of external thread 811 of tension bar 81 required for attaching tension bar 81 for pull-out test.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a rock bolt that is placed in a natural ground of a tunnel such as a mountain tunnel, a lock bolt plate that is fixed together with the lock bolt on the natural ground, a lock bolt installation structure that uses the lock bolt plate, The present invention relates to a loading test method.

  When a rock bolt is placed on a natural mountain such as a mountain tunnel, a primary lining sprayed concrete 102 is generally provided on the surface of the natural mountain 101 following the shape of the tunnel space, and formed on the shotcrete 102 and the natural mountain 101. The fixing hole 104 such as cement mortar is filled in the bore hole 103 and the lock bolt 105 is inserted, and the male screw 106 on the base end side of the lock bolt 105 is slightly projected from the placing surface which is the surface of the shotcrete 102. A nut 108 is tightened and fixed through a washer 107 for receiving a load on the protruding male screw 106 (see FIG. 10). Thereafter, a waterproof sheet 109 is laid inside the tunnel space so as to cover the protruding portion of the male screw 106, the nut 108 and the washer 107, and further, lining concrete not shown is provided.

  Furthermore, when driving a lock bolt, in order to confirm the fixing state of the lock bolt, a load resistance may be tested by applying a pulling force. As shown in FIG. 11, this pull-out test is performed by attaching a tension bar 110 to the protruding portion of the male screw 106 of the lock bolt 105 fixed to the ground 101, attaching a center hole jack 111 to the tension bar 110, and pulling out in stages. This is performed by loading a force and reading the extension amount of the lock bolt 105 with a displacement meter (not shown).

  In addition, the male screw 106 of the lock bolt 105 protruding from the placement surface and the nut 108 screwed to the lock bolt cause damage to the waterproof sheet 109 laid on the inner side. Ingredients have been proposed. In this fixing device, the nut is engaged with the seat plate so that the tapered outer peripheral surface of the nut is aligned with the tapered hole of the seat plate, and a part of the fixing bolt protrudes from the placement surface on the base end side of the lock bolt. A nut is screwed onto a male screw, and the nut is fixed with a grout material together with a lock bolt. In the fixed state, the outer surface of the seat plate and the end surface on the base end side of the lock bolt are substantially flush with respect to the outer surface of the seat plate. Is to be placed.

JP 2017-110486 A

  By the way, although the fixing tool of patent document 1 has arranged the outer surface of a seat board, the outer surface of a nut, and the end surface of the base end side of a lock bolt on the substantially the same surface, it aims at the damage prevention of a waterproof sheet. It is not possible to deal with the case where a pull-out test is required. That is, in this installation structure of the fixing tool, the nut is fixed with the grout material together with the lock bolt, so that the nut fixed from the lock bolt in the fixed state cannot be removed, and the tension bar for the pull-out test is applied to the lock bolt. It is difficult to attach to the protruding part from the installation surface. Therefore, it is hoped that it is possible to prevent the waterproof sheet from being damaged by minimizing the protrusion of the lock bolt from the placement surface, and at the same time to perform a lock bolt pull-out test. It is rare.

  The present invention is proposed in view of the above-described problems, and it is possible to prevent the waterproof sheet from being damaged by suppressing the protrusion of the lock bolt from the placement surface to the maximum, and at the same time, It is an object of the present invention to provide a lock bolt plate that enables a pull-out test, a lock bolt installation structure using the lock bolt plate, and a lock bolt loading test method.

The lock bolt plate of the present invention is formed integrally with the nut portion so as to expand outward from the base end portion of the nut portion, and a nut portion having an internal thread formed therein, and the nut portion protrudes. It is provided with a substantially flat flange part with a bearing surface on the side, and the length of the female screw is the screwed length with the male screw of the lock bolt to obtain the required pulling strength, and the tension bar for pulling test The length of the tension bar is greater than the total length of the threaded engagement with the male thread of the tension bar.
According to this, when the lock bolt and the lock bolt plate are installed on the ground, the base end surface of the lock bolt does not protrude from the lock bolt plate, and the lock bolt protrudes from the setting surface. The portion can be limited to the base end portion and the flange portion of the nut portion of the lock bolt plate. Therefore, the protrusion from the placement surface at the place where the lock bolt is placed can be suppressed to the maximum, and the waterproof sheet laid so as to cover the projecting portion from the placement surface can be prevented. Further, since the protruding amount of the base end portion of the nut portion and the flat flange portion from the placement surface is considerably small, the waterproof sheet can be laid so as to substantially follow the placement surface and waterproof in the tunnel space. It is also possible to place the lining concrete placed inside the sheet with substantially the same thickness in the circumferential direction. In addition, the internal thread of the nut part is screwed with the external thread of the tension bar, which is required for mounting the tension bar for the pull-out test, in addition to the threading length required for engaging with the external thread of the lock bolt. Because the length is secured, when the lock bolt and lock bolt plate are installed on the ground, the tension bolt is attached and the lock bolt pull-out test is performed without the need for removing the member. Is possible.

The plate for a lock bolt according to the present invention is characterized in that a shoulder portion opposite to the bearing surface in the thickness direction of the flange portion is formed as a rounded surface that is convex outward.
According to this, damage to the waterproof sheet due to the shape of the shoulder portion of the flange portion can also be prevented, and damage to the waterproof sheet laid so as to cover the protruding portion from the placement surface can be more reliably prevented. . Also, by making the shape of the shoulder part of the flange part convex outward, the thickness is increased as much as possible to the vicinity of the peripheral edge of the flange part, and higher bearing strength and support force to earth pressure are provided. This can be achieved, and it is possible to prevent the shape of the flange portion around the shoulder portion from being lost.

The lock bolt plate of the present invention is formed of a bottom plate and a peripheral wall, and a cap having a lock bolt insertion hole at the center of the bottom plate is fitted on the distal end side of the nut portion, and the distal end of the nut portion and the cap A gap for retightening is formed between the bottom plate and the bottom plate.
According to this, when fixing with the fixing material and installing the lock bolt and the lock bolt plate on the ground, it is possible to prevent the fixing material from adhering to the cap and from adhering to the nut portion. A gap for retightening can be secured between the bottom plate of the cap. Therefore, if the bearing surface of the flange portion of the rock bolt plate and the placement surface such as the surface of shotcrete are separated due to the displacement of the natural ground after construction, the lock bolt plate should be tightened. Can do.

The lock bolt plate of the present invention is characterized in that the outer peripheral surface of the nut portion is formed with a tapered surface that gradually decreases in diameter toward the tip.
According to this, when fixing with the fixing material and installing the lock bolt and the plate for the lock bolt on the ground, the nut portion is easily cut off from the fixing material by the taper surface of the outer periphery of the nut portion. If the bearing surface of the flange portion of the rock bolt plate and the placement surface such as the surface of shotcrete are separated due to the displacement of the natural ground after construction, the lock bolt plate can be retightened .

In the lock bolt installation structure of the present invention, the male screw on the base end side of the lock bolt is screwed from the distal end side of the female screw of the nut portion of the lock bolt plate of the present invention to the middle position of the female screw, and the lock bolt is It is placed in a bore hole in a natural ground and fixed by a fixing material, the placement surface is pressed by the bearing surface of the flange portion, and the base end surface of the lock bolt is arranged on the natural ground side from the placement surface. It is characterized by that.
According to this, the base end surface of the lock bolt is disposed on the ground side from the placement surface that does not clearly protrude from the lock bolt plate, and the protruding portion from the placement surface at the place where the lock bolt is placed is located on the lock bolt plate. It can be reliably limited to the base end portion and the flange portion of the nut portion. Therefore, the protrusion from the placement surface at the place where the lock bolt is placed can be suppressed to the maximum, and the waterproof sheet laid so as to cover the projecting portion from the placement surface can be prevented. Further, since the protruding amount of the base end portion of the nut portion and the flat flange portion from the placement surface is considerably small, the waterproof sheet can be laid so as to substantially follow the placement surface and waterproof in the tunnel space. It is also possible to place the lining concrete placed inside the sheet with substantially the same thickness in the circumferential direction. In addition, the internal thread of the nut part is screwed with the external thread of the tension bar, which is required for mounting the tension bar for the pull-out test, in addition to the threading length required for engaging with the external thread of the lock bolt. Since the length is secured, the pull-out test of the lock bolt can be performed by attaching the tension bar to the lock bolt plate of the lock bolt installation structure as it is without the need for removing the member.

In the lock bolt loading test method of the present invention, the male screw of the tension bar is screwed from the base end side of the female screw of the nut portion to the middle position of the female screw in the lock bolt installation structure of the present invention, and a center hole jack is used. A pulling force is loaded stepwise on the lock bolt via the tension bar.
According to this, it is possible to perform the lock bolt pull-out test by attaching the tension bar to the lock bolt plate of the lock bolt installation structure as it is without the need for removing the member or the like.

  According to the present invention, it is possible to prevent the waterproof sheet from being damaged by maximally suppressing the protrusion from the placement surface at the place where the lock bolt is placed, and at the same time to perform a lock bolt pull-out test. Become.

(A) is a front view of the plate for lock bolts of 1st Embodiment by this invention, (b) is the side view, (c) is AA sectional drawing of the figure (a). BRIEF DESCRIPTION OF THE DRAWINGS (a) is a schematic explanatory drawing of the tunnel in which the lock bolt plate and the lock bolt of the first embodiment are installed, and (b) is a cross-sectional explanatory drawing showing the details of the B part of FIG. Cross-sectional explanatory drawing which shows a part of natural ground in which the plate for lock bolts of 1st Embodiment and the lock bolt were installed. (A) is a partial cross-sectional explanatory view showing the lock bolt plate and tension bar of the first embodiment in a state where the lock bolt is screwed, and (b) is a diagram showing the lock bolt plate and the lock bolt in the first embodiment. Partial cross-sectional explanatory drawing which shows the state by which the tension bar was screwed together. (A) is a perspective view showing a lock bolt plate and a tension bar of the first embodiment in a state where the lock bolt is screwed, and (b) is a lock bolt of the first embodiment in a state where the lock bolt is screwed. The perspective view of the state in which the loading test apparatus was attached to the plate for operation. The partial cross section explanatory drawing explaining the retightening of the plate for lock bolts in the natural ground where the plate for lock bolts and the lock bolt of 1st Embodiment were installed. (A) is a front view of the plate for lock bolts of 2nd Embodiment by this invention, (b) is the side view, (c) is CC sectional drawing of the figure (a). Sectional explanatory drawing of the part corresponded in FIG.2 (b) in which the plate for lock bolts and lock bolt of 2nd Embodiment were installed. Cross-sectional explanatory drawing which shows a part of natural ground in which the plate for lock bolts of 2nd Embodiment and the lock bolt were installed. Cross-sectional explanatory drawing which shows a part of natural ground of the tunnel in which the conventional lock bolt was installed. Cross-sectional explanatory drawing explaining the pull-out test of the lock bolt installed in the natural ground of the conventional tunnel.

[Plate for Lock Bolt and Lock Bolt Installation Structure of First Embodiment]
As shown in FIG. 1, the lock bolt plate 1 according to the first embodiment of the present invention is integrally formed with the nut portion 2 so as to extend outward from the base portion 21 of the nut portion 2 and the nut portion 2. It is comprised from the flange part 3 which has. The nut portion 2 and the flange portion 3 in the illustrated example are each made of steel.

  An internal thread 23 is formed inside the nut portion 2, and the internal thread 23 is formed from the tip 22 in the axial direction of the nut portion 2. The female screw 23 is formed to the length of the most part of the nut portion 2 up to a midway position to the base end 21. A tapered surface 241 is formed on the outer peripheral surface 24 of the nut portion 2 so as to expand toward the base end 21 at a part of the periphery of the base. Further, a hexagonal hole-like engagement hole 25 is formed at a predetermined depth from the base end 21 in the nut portion 2, and the engagement hole 25 is formed so as to form a step at the center of the base end 21. The engagement hole 25 communicates with the female screw 23 inside the nut portion 2.

  The length of the female screw 23 of the nut portion 2 is such that the threaded length with the male screw 62 of the lock bolt 6 to obtain the required pulling strength described later, and the tension bar 81 required for mounting the tension bar 81 for pulling test. Is set to a length that is equal to or greater than the total length of the threaded engagement with the male screw 811. The screwing length of the female screw 23 with the male screw 62 of the lock bolt 6 that provides the required pulling strength is the screwing length of the female screw 23 that can withstand the tensile load corresponding to the required pulling strength and the male screw 62 of the lock bolt 6. is there. The threaded length of the tension bar 81 and the male screw 811 required for attaching the tension bar 81 of the female screw 23 corresponds to at least the required pulling strength required for the lock bolt 6 and the lock bolt plate 1 described above. This is a screwed length of the female screw 23 that can withstand the tensile load to be engaged with the male screw 811 of the tension bar 81.

  The flange portion 3 is formed in a flat plate shape, and is formed in a substantially disc shape in the illustrated example. The surface of the flange portion 3 on which the nut portion 2 protrudes is a substantially flat bearing surface 31, and the bearing surface 31 supports a placement surface 17 of the lock bolt 6 described later when the lock bolt plate 1 is installed. It is like that. Further, the shoulder portion 32 opposite to the bearing surface 31 in the thickness direction of the flange portion 3 is formed to be an outwardly convex round surface.

  Furthermore, a plastic cap 4 is externally fitted on the tip side of the nut portion 2 in the first embodiment. The cap 4 is formed by a bottom plate 41 and a peripheral wall 42, and a lock bolt insertion hole 43 is formed at the center of the bottom plate 41. The cap 4 is externally fitted and arranged on the nut portion 2 so that the end of the peripheral wall 42 opposite to the bottom plate 41 is hooked in the vicinity of the rising portion of the tapered surface 241 of the nut portion 2, and is arranged at this position. In this state, a retightening gap 5 is provided between the tip 22 of the nut portion 2 and the bottom plate 41 of the cap 4.

  The lock bolt plate 1 of the first embodiment is installed together with the lock bolt 6 in, for example, a tunnel shown in FIG. In FIG. 2, 11 is a tunnel space, 12 is a natural ground of the tunnel, 13 is shotcrete placed along the pit wall of the natural pile 12, and 14 is laid so as to substantially follow the inner peripheral surface of the shotcrete 13. A waterproof sheet 15 is secondary lining concrete that is placed inside the waterproof sheet 14.

  As shown in FIGS. 2 and 3, the shotcrete 13 and the natural ground 12 have a bore hole 16 formed in a direction substantially orthogonal to the pit wall, and a lock bolt 6 is placed in the bore hole 16, and cement mortar. The fixing material 7 is fixed. The lock bolt 6 has a main body 61 and a male screw 62 formed on the base end side of the main body 61. The lock bolt 6 is inserted from the front end of the main body 61 to the back side of the bore hole 16, and the male screw 62 becomes the hole side of the bore hole 16. Are arranged as follows. The base end surface 621 of the male screw 62, which is the base end surface of the driven lock bolt 6, is disposed in the bore hole 16 without projecting outward from the bore hole 16, and is more natural than the driving surface 17 of the lock bolt 6. It is arranged on the 12 side.

  The lock bolt plate 1 is arranged so that the nut portion 2 and the cap 4 are inserted into the bore hole 16, and the male screw 62 of the lock bolt 6 is inserted into the insertion hole 43 of the cap 4 in the bore hole 16. A male screw 62 is screwed from the distal end side of the female screw 23 of the nut portion 2 to a middle position of the female screw 23. In the bore hole 16, the fixing material 7 is basically not attached to the nut portion 2 of the lock bolt plate 1, but is attached to the outer periphery of the cap 4. The bearing surface 31 of the flange portion 3 of the lock bolt plate 1 installed in the bore hole 16 together with the lock bolt 6 presses the placing surface 17 which is the inner surface of the shotcrete 13 in the illustrated example.

  When constructing the installation structure of the lock bolt plate 1 and the lock bolt 6, the fixing material 7 such as cement mortar is filled into the borehole 16 formed in the shotcrete 13 and the ground 12, and the fixing material 7 is fixed. The lock bolt 6 is inserted into the bore hole 16 before being connected. When the lock bolt 6 is inserted, the female screw 23 of the lock bolt plate 1 is screwed into the male screw 62 of the lock bolt 6 by a predetermined length, and the lock bolt plate 1 is attached to the lock bolt 6 in advance. Insert the lock bolt 6 to which is attached. That is, the nut portion 2 of the lock bolt plate 1 is also provided in the bore hole 16 as the lock bolt 6 is inserted.

  Further, the bearing surface 31 of the flange portion 3 of the lock bolt plate 1 is brought into contact with the placement surface 17 of the shotcrete 13 by inserting the lock bolt 6 into the bore hole 16. Then, the lock bolt 6 embedded in the bore hole 16 filled with the fixing material 7 and the lock bolt plate 1 attached thereto are fixed in place by fixing the fixing material 7, and the lock bolt plate is fixed. One bearing surface 31 is fixed so as to abut against the placement surface 17 and urge the placement surface 17.

  When performing a loading test in which a pulling force is loaded in the installation structure of the lock bolt plate 1 and the lock bolt 6, the lock bolt fixed to the bore hole 16 as shown in FIGS. 2, 3, 4, and 5. The male screw 811 of the tension bar 81 is screwed onto the female screw 23 of the nut portion 2 of the working plate 1 from the proximal end side of the female screw 23 to the middle position of the female screw 23. That is, the male screw 811 of the tension bar 81 is screwed to the female screw 23 of the nut portion 2 in a state where the male screw 62 of the lock bolt 6 is screwed from the opposite side to the lock bolt 6 with a required length.

  Then, the center hole jack 82 is attached to the protruding portion of the tension bar 81 from the flange portion 3. In this state, the force generated by the hydraulic jack 83 is transmitted to the center hole jack 82, the pulling force is loaded stepwise on the tension bar 81 by the center hole jack 82, and the step is applied to the lock bolt 6 via the tension bar 81. The pulling force is loaded and the displacement tester 84 reads the extension amount of the lock bolt 6 to perform a loading test. 5 is a pedestal for receiving the center hole jack 82, and 86 is an adjusting leg that abuts against the placement surface 17 and lifts the pedestal 85 from the placement surface.

  According to the first embodiment, when the lock bolt 6 and the lock bolt plate 1 are installed on the ground 12, the base end surface 621 of the lock bolt 6 is not protruded from the lock bolt plate 1, and the lock bolt 6 The protruding portion from the placement surface 17 at the placement location can be limited to the base end portion of the nut portion 2 of the lock bolt plate 1 and the flange portion 3. Therefore, the protrusion from the placement surface 17 at the place where the lock bolt 6 is placed can be suppressed to the maximum, and the waterproof sheet 14 laid so as to cover the projection portion from the placement surface 17 can be prevented.

  Further, since the protruding amount of the base end portion of the nut portion 2 and the flat flange portion 3 from the placement surface 17 is considerably small, the waterproof sheet 14 can be laid so as to substantially follow the placement surface 17. In addition, the lining concrete 15 that is placed inside the waterproof sheet 14 in the tunnel space 11 can also be placed with substantially the same thickness in the circumferential direction. Further, since the waterproof sheet 14 can be laid so as to substantially follow the placing surface 17, it is possible to prevent a cavity from being generated on the back surface of the lining concrete 15. Further, since the projecting portion of the base portion of the nut portion 2 and the flat flange portion 3 from the placement surface 17 is considerably small, the waterproof sheet 14 can be laid so as to substantially follow the placement surface 17. It is also possible to prevent the cracking of the lining concrete 15 due to the restraint of the lining concrete 15 to the portion.

  Further, apart from the screwing length required for screwing the female screw 23 of the nut portion 2 with the male screw 62 of the lock bolt 6, the tension bar 81 required for attaching the tension bar 81 for pull-out test is used. Since the threaded length with the male screw 811 is secured, the tension bar 81 can be attached without the need for removing the member when the lock bolt 6 and the lock bolt plate 1 are installed on the ground 12. It becomes possible to perform the pull-out test of the lock bolt 6 by attaching.

  Further, by making the shape of the shoulder portion 32 of the flange portion 3 convex outward, damage to the waterproof sheet 14 due to the shape of the shoulder portion of the flange portion 3 is prevented, and the protrusion from the placement surface 17 is prevented. Damage to the waterproof sheet 14 laid so as to cover the portion can be more reliably prevented. Furthermore, the thickness is increased as much as possible to the vicinity of the peripheral edge of the flange portion 3, and a higher bearing strength and a supporting force against earth pressure can be exhibited, and the shape around the shoulder portion of the flange portion 3 is lacking. This can be prevented.

  Further, the cap 4 is externally fitted to the tip end side of the nut portion 2 to form an additional tightening gap 5 so that the fixing member 7 fixes the lock bolt 6 and the lock bolt plate 1 to the ground 12. In this case, the fixing material 7 can be attached to the bottom plate 41 of the cap 4 and the like, and can be prevented from adhering to the tip of the nut portion 2. The gap 5 can be secured. Therefore, as shown in FIG. 6, when the bearing surface 31 of the rock bolt plate 1 and the placement surface 17 of the shotcrete 13 are separated from each other due to the displacement of the ground 12 after the construction, The lock bolt plate 1 can be easily tightened by inserting the tool 9 in 25.

  Further, according to the lock bolt loading test method of the first embodiment, the tension bar 81 is directly attached to the lock bolt plate 1 of the lock bolt installation structure without the need for removing the member or the like. A pull-out test can be performed.

[Lock Bolt Plate and Lock Bolt Installation Structure of Second Embodiment]
As shown in FIG. 7, the lock bolt plate 1a according to the second embodiment of the present invention is integrally formed with the nut portion 2a and the nut portion 2a so as to extend outward from the base end 21a of the nut portion 2a. And the flange portion 3a. The nut portion 2a and the flange portion 3a in the illustrated example are also made of steel, like the lock bolt plate 1 of the first embodiment. The configuration other than the lock bolt plate 1a, for example, the configuration of the lock bolt 6, the tension bar 81, and the like is the same as that of the first embodiment.

  A female screw 23a is formed on the inner side of the nut portion 2a, and the female screw 23a is formed from the distal end 22a to the proximal end 21a in the axial direction of the nut portion 2a. The outer peripheral surface 24a of the nut portion 2a is formed as a tapered surface that gradually decreases in diameter from the root portion of the flange portion 3a toward the tip 22a. Further, the length of the female screw 23a of the nut portion 2a is the same as the length of the female screw 23 in the first embodiment, and the screwing length with the male screw 62 of the lock bolt 6 to obtain a required pulling strength, and for the pulling test. The length is set to be equal to or greater than the total length of the tension bar 81 and the threaded length of the male screw 811 required for attaching the tension bar 81.

  The flange portion 3a is formed in a flat plate shape, and is formed in a substantially disk shape in the illustrated example. The surface of the flange portion 3a on which the nut portion 2a protrudes is a substantially flat bearing surface 31a, and the bearing surface 31a supports the placing surface 17 of the lock bolt 6 when the lock bolt plate 1a is installed. It has become. Further, the shoulder portion 32a opposite to the bearing surface 31a in the thickness direction of the flange portion 3a is formed to be an outwardly convex round surface, like the shoulder portion 32 of the first embodiment.

  In the lock bolt plate 1a of the second embodiment, a rotation engagement hole 33a is formed in the flange portion 3a instead of the hexagonal hole engagement hole 25 in the first embodiment as a tool engagement portion. ing. A plurality of engagement holes 33a are provided in the circumferential direction at substantially intermediate positions in the radial direction of the flange portion 3a, and are provided at two locations in the illustrated example. When retightening with the lock bolt plate 1a, a tool having a protrusion at a position corresponding to the engagement hole 33a is used, and the protrusion of the tool is engaged with the engagement hole 33a to increase the lock bolt plate 1a. It is possible to perform tightening.

  Similarly to the first embodiment, the lock bolt plate 1a of the second embodiment is also installed in the tunnel together with the lock bolt 6 (see FIGS. 8 and 9). That is, the lock bolt 6 is placed in the bore hole 16 formed in the shotcrete 13 and the natural ground 12, and the lock bolt 6 arranged so that the male screw 62 is located on the hole side of the bore hole 16 is fixed to cement mortar or the like. Fixing with material 7. The base end surface 621 of the male screw 62 that is the base end surface of the driven lock bolt 6 is disposed in the bore hole 16 without protruding outward from the bore hole 16, and is closer to the ground 12 than the driving surface 17 of the lock bolt 6. Placed in.

  The lock bolt plate 1a is arranged so that the nut portion 2a is inserted into the bore hole 16. In the bore hole 16, the male screw 62 of the lock bolt 6 extends from the front end side of the female screw 23a of the nut portion 2a to the middle of the female screw 23a. Screwed to the position. In the bore hole 16, the fixing material 7 is attached to the tapered outer peripheral surface 24a of the nut portion 2a of the lock bolt plate 1a. However, since the outer peripheral surface 24a is tapered, the fixing material 7 is cut off from the fixing material 7. It has become easier. The bearing surface 31 a of the flange portion 3 a of the lock bolt plate 1 a installed in the bore hole 16 together with the lock bolt 6 presses the placing surface 17 that is the inner surface of the shotcrete 13.

  When the installation structure of the lock bolt plate 1a and the lock bolt 6 of the second embodiment is constructed, it can be installed by the same process as the installation structure of the first embodiment. A lock bolt plate 1a is attached to the lock bolt 6 in advance by screwing the female screw 23a of the lock bolt plate 1a by a predetermined length, and before the fixing material 7 filled in the bore hole 16 is solidified, the lock bolt plate It is constructed by inserting a lock bolt 6 to which a plate 1a is attached.

  Furthermore, it is possible to carry out the same procedure as in the first embodiment when performing a loading test in which a pulling force is loaded in the installation structure of the lock bolt plate 1a and the lock bolt 6 of the second embodiment. That is, the male screw 811 of the tension bar 81 is screwed to the female screw 23a of the nut portion 2a of the lock bolt plate 1a in a state in which the male screw 62 of the lock bolt 6 is screwed from the opposite side to the lock bolt 6 with a required length. A center hole jack 82 is attached to the protruding portion of the tension bar 81 from the flange portion 3a, the pulling force is loaded stepwise on the lock bolt 6 via the tension bar 81, and the displacement meter 84 reads the extension amount of the lock bolt 6. Perform a loading test.

  According to the second embodiment, a corresponding effect can be obtained from the configuration corresponding to the first embodiment. Further, when the fixing member 7 is fixed and the lock bolt 6 and the lock bolt plate 1a are installed on the ground mountain 12, the nut portion 2a is easily cut off from the fixing member 7 by the tapered outer peripheral surface 24a of the nut portion 2a. If the bearing surface 31a of the flange portion 3a of the lock bolt plate 1a and the placing surface 17 are separated due to the displacement of the natural ground after the construction due to the edge cutting, the lock bolt plate 1a is tightened. It can be performed.

[Included scope of the invention disclosed herein]
The invention disclosed in the present specification is specified by changing the partial contents to other contents disclosed in the present specification within the applicable range in addition to the inventions and embodiments listed as inventions. Or specified by adding other contents disclosed in this specification to these contents, or specified by deleting these partial contents to the extent that partial effects can be obtained and creating a higher level concept. Is included. The invention disclosed in this specification includes the following modified examples and added contents.

  For example, in the lock bolt plate of the present invention, the length of the female screw is the length of the threaded engagement with the male screw of the lock bolt that provides the required pulling strength, and the tension bar required for mounting the tension bar for the pull-out test. This includes the case where the length is greater than the total length of the male screw with the male screw, but in order to provide a certain margin and to cope with dimensional errors, the length of the female screw is set to the required pulling strength. A length exceeding the sum of the threaded length of the lock bolt with the male thread of the lock bolt and the threaded length of the male thread of the tension bar required for mounting the tension bar for the pull-out test. A length of plus α such as a pitch is preferable.

  Further, in the lock bolt plate of the present invention, the configuration in which the cap is fitted on the tip end side of the nut portion to form the additional tightening gap is formed by connecting the end portion of the peripheral wall of the cap 4 of the first embodiment to the nut portion 2. Other than the configuration in which the taper surface 241 is hooked in the vicinity of the rising portion, it is appropriate, for example, the peripheral wall of the cap is formed so that the diameter gradually narrows toward the bottom plate, and this cap is externally fitted to the distal end side of the nut portion and increased. It is possible to adopt a configuration that is arranged at a position where a fastening gap is provided. In addition, it is preferable that the material of the cap in the present invention is lower in strength and more easily deformable than the material of the nut portion and the flange portion or the material of the nut portion.

  Further, the lock bolt installation structure of the present invention in which the male screw on the base end side of the lock bolt is screwed from the distal end side of the female screw of the nut portion of the lock bolt plate to the middle position of the female screw is the inner peripheral surface of the shotcrete of the tunnel In addition to the configuration provided over the entire area where the lock bolt is installed, such as the entire configuration, it is also possible to provide the configuration where only a part of the lock bolt installation region where the pull-out test is performed is provided. In this case, the male screw of the lock bolt may be screwed into all the female screws of the lock bolt plate of the present invention at the place where the lock bolt is not subjected to the pull-out test.

  The present invention can be used, for example, when a rock bolt is installed in a mountain tunnel or the like where a waterproof sheet is constructed.

DESCRIPTION OF SYMBOLS 1, 1a ... Rock bolt plate 2, 2a ... Nut part 21, 21a ... Base end 22, 22a ... Tip 23, 23a ... Female screw 24, 24a ... Outer peripheral surface 241 ... Tapered surface 25 ... Engagement hole 3, 3a ... Flange Part 31, 31a ... Bearing surface 32, 32a ... Shoulder 33a ... Engagement hole 4 ... Cap 41 ... Bottom plate 42 ... Peripheral wall 43 ... Insertion hole 5 ... Air gap 6 ... Lock bolt 61 ... Main body 62 ... Male screw 621 ... Base end face 7 ... Fixing material 81 ... Tension bar 811 ... Male screw 82 ... Center hole jack 83 ... Hydraulic jack 84 ... Displacement meter 85 ... Pedestal, 86 ... Adjusting leg 9 ... Tool 11 ... Tunnel space 12 ... Mtyama 13 ... Spring concrete 14 ... Waterproof sheet 15 ... lining concrete 16 ... bore hole 17 ... placing surface 101 ... ground mountain 102 ... shotcrete 103 ... bore hole 104 Fixing material 105 ... lock bolt 106 ... external thread 107 ... washer 108 ... Nut 109 ... waterproof sheet 110 ... tension bar 111 ... center hole jack

Claims (6)

A nut portion on which an internal thread is formed, and
A substantially flat flange portion that is integrally formed with the nut portion so as to spread outward from the base end portion of the nut portion, and the protruding side of the nut portion is a bearing surface;
The length of the female screw is a screwed length with a male screw of a lock bolt that provides a required pulling strength, and a screwed length with a male screw of the tension bar required for mounting a tension bar for a pull-out test. A plate for rock bolts characterized by having a length that is greater than the total length.   The rock bolt plate according to claim 1, wherein a shoulder portion opposite to the bearing surface in the thickness direction of the flange portion is formed as an outwardly convex round surface. A cap formed of a bottom plate and a peripheral wall and having a lock bolt insertion hole at the center of the bottom plate is externally fitted to the tip side of the nut portion,
The lock bolt plate according to claim 1 or 2, wherein a retightening gap is formed between a tip of the nut portion and the bottom plate of the cap.   The lock bolt plate according to claim 1 or 2, wherein an outer peripheral surface of the nut portion is formed by a tapered surface that gradually decreases in diameter toward the tip. The male screw on the base end side of the lock bolt is screwed from the distal end side of the female screw of the nut portion of the lock bolt plate according to any one of claims 1 to 4 to an intermediate position of the female screw,
The lock bolt is placed in a bore hole in a natural mountain and fixed with a fixing material,
The placing surface is pressed by the bearing surface of the flange portion,
The lock bolt installation structure characterized by the base end surface of the said lock bolt being arrange | positioned in the said natural ground side rather than the said placement surface. The male screw of the tension bar is screwed from the base end side of the female screw of the nut portion to the midway position of the female screw in the lock bolt installation structure according to claim 5;
A loading test method for a lock bolt, wherein a pulling force is loaded stepwise on the lock bolt via the tension bar by a center hole jack.

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