JP2022180263A - Rock bolt structural body and natural ground reinforcement structure - Google Patents

Abstract

To provide a natural ground reinforcement structure allowing a rock bolt structural body to be securely fixed on the natural ground over a long length even where the natural ground has a lot of cracks.SOLUTION: A rock bolt structural body comprises: a steel pipe expansion type rock bolt 2 in which a front end is sealed and a screwed part having a water injection port is arranged at a rear end; a hollow rock bolt 3 for fixing a fixing material inside which an injected water guide space is provided along an axial direction; and a joint sleeve 4 which is communicated in the axial direction and in which a screw part is formed in a front part, wherein the screw part of the joint sleeve 4 and the screwed part of the steel pipe expansion type rock bolt 2 are screwed as well as a front part of the hollow rock bolt 3 and a rear part of the joint sleeve 4 are secured, and an annular seal member 42 liquid-tightly sealed from an outer part by pressing force in a screw-in direction of the screw part and the screwed part is arranged on the joint sleeve 4.SELECTED DRAWING: Figure 2

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rock bolt structure in which a hollow rock bolt is fixed with a fixing material injected into a borehole, and a ground reinforcement structure including this rock bolt structure.

Conventionally, a ground reinforcement structure is known in which a hollow rock bolt is fixed by a fixing material injected into a borehole. For example, in Patent Document 1, a hollow rock bolt with a drill bit attached to its tip is rotated to drill a hole in the ground, and the hollow rock bolt is added to drill a hole to a predetermined depth. A structure is disclosed in which grout is injected between the hollow rock bolt and the perforated wall surface through the hollow part of the hole, and the grout is solidified to fix the hollow rock bolt (Patent Document 1, paragraphs [0002], [0018 ]reference).

Japanese Patent Application Laid-Open No. 2009-97260

By the way, when hollow rock bolts are added to drive a long length deep into the ground and fixed by injecting fixing material, a fixing material with high fluidity is used to inject the fixing material into the deep layer of the ground. need to use. However, in the case of ground with many cracks, the high fluidity of the ground causes the fixing material to flow into the cracks, and escape before the fixing material solidifies and escape from between the hollow rock bolt and the drilled wall surface. A problem arises in that the fixing material runs out. On the other hand, if an anchoring material with low fluidity such as hard-kneaded mortar is used, it becomes impossible to inject the anchoring material deep into the hole, making it difficult to anchor the hollow rock bolts located in the deep layer to the ground. cause the following problems.

In view of the above problems, the present invention proposes a rock bolt structure that can be reliably fixed to the ground over a long length even if there are many cracks in the ground, and a ground reinforcement provided with this rock bolt structure. It is intended to provide structure. For the sake of convenience in explaining the present invention, hereinafter, the sides arranged on the far side of the drilling when the lock bolt is installed in the drilling are defined as "front" and "tip", and the terms "front end", "front part" and "tip" are used. ” may be expressed by using terms such as “rear”, “rear end”, and “rear side”, with the side arranged on the mouth side of the perforation as “rear”.

The rock bolt structure of the present invention comprises a steel pipe expansion lock bolt having a closed front end and a threaded portion having a water inlet at the rear end, and a water inlet space provided inside along the axial direction. and a joint sleeve having a threaded portion formed in a front portion thereof, the threaded portion of the joint sleeve and the steel tube expansion type lock bolt communicating with each other in an axial direction. and the screwed portion of the hollow lock bolt is fixed to the front portion of the hollow lock bolt and the rear portion of the joint sleeve, and the threaded portion and the screwed portion are screwed in the direction of screwing. The joint sleeve is characterized in that an annular seal member is provided on the joint sleeve for liquid-tight sealing with the outside when pressed against the joint sleeve.
According to this, when a long rock bolt structure is driven into the deep layer of the ground and fixed, it can be fixed by friction fixation of the steel pipe expansion type rock bolt in the expanded state on the far side of the drilled hole. It is no longer necessary to inject into the deep layer of the ground and the inner side of the drilled hole using a fixing material with high resistance. That is, even when a rock bolt structure is fixed over a long length to a ground with many cracks, there is a problem that the highly fluid fixing material escapes from the cracks and disappears before it solidifies. Therefore, the rock bolt structure can be reliably fixed to the ground over a long length by both the friction fixing and the fixing of the fixing material. In addition, it is possible to use a fixing material with low fluidity, such as hard-kneaded mortar, because it can be fixed by friction fixing in the expanded state of the steel pipe expansion type rock bolt on the back side of the drilled hole in the ground. The diversity of possible fixing materials can be increased. In addition, when pressurized water is injected into the inside of the steel pipe expansion lock bolt using the water injection space of the hollow lock bolt and the water inlet of the steel pipe expansion lock bolt to make it expand, the liquid of the annular seal material of the joint sleeve Due to the sealing, it is possible to reliably prevent the injected water from leaking from the gap between the threaded portion of the joint sleeve and the threaded portion of the steel pipe expansion lock bolt. It is possible to increase the certainty of pressurized water injection to the steel pipe expansion rock bolt and expansion deformation.

In the lock bolt structure of the present invention, the threaded portion of the steel pipe expansion lock bolt is a male threaded portion, the screwed portion of the joint sleeve is a female threaded portion, and a root of the female threaded portion is provided behind the male threaded portion. It is characterized in that the annular sealing material is provided to be pressed at the end.
According to this, the steel tube expansion lock bolt and the joint sleeve can be screwed together with high strength and stability. Further, the annular seal member at the base of the female threaded portion of the joint sleeve is pressed by the rear end portion of the male threaded portion of the steel tube expansion lock bolt, so that the annular seal member can be liquid-tightly sealed. In addition, since the joint sleeve is transported and brought into the site with the annular seal disposed at the base of the internal thread portion of the joint sleeve, damage to the annular seal is prevented.

In the lock bolt structure of the present invention, the threaded portion of the steel pipe expansion lock bolt is a female thread portion, the threaded portion of the joint sleeve is a male thread portion, and a root of the male thread portion is provided behind the female thread portion. It is characterized in that the annular sealing material is provided to be pressed at the end.
According to this, the steel tube expansion lock bolt and the joint sleeve can be screwed together with high strength and stability. Further, the annular seal member at the root of the male threaded portion of the joint sleeve is pressed by the rear end portion of the female threaded portion of the steel tube expansion lock bolt, so that the annular seal member can be liquid-tightly sealed. In addition, by arranging the ring-shaped seal material at the base of the male threaded portion of the joint sleeve, it is possible to visually check if the ring-shaped seal material is dislodged or displaced when connecting the steel tube expansion lock bolt and the hollow lock bolt. , can increase the certainty of construction.

In the rock bolt structure of the present invention, a connection portion to which a front portion of a water injection pipe can be detachably connected is provided inside the rear side of the threaded portion of the joint sleeve, and the hole wall of the bore hole in the ground and the hollow A discharge hole through which a fixing material can be injected between the outer surface of the lock bolt and the outer surface of the joint sleeve is formed in the peripheral wall of the joint sleeve on the rear side of the connecting portion or in the peripheral wall of the hollow lock bolt. It is characterized by
According to this, it is possible to introduce and connect the water injection pipe to the rear side of the threaded portion of the joint sleeve, pressurize water injection into the steel pipe expansion lock bolt by the water injection pipe, and remove the steel pipe expansion lock bolt. The certainty of expansion deformation can be further enhanced. In addition, by forming a discharge hole through which the fixing material can be injected between the hole wall and the outer surface of the drilled hole in the ground in the joint sleeve or the hollow rock bolt arranged on the mouth side of the drilled hole, of the fixing material can be suppressed. Further, when a discharge hole into which the fixing material can be injected is formed in the peripheral wall of the joint sleeve, the fixing material can be more reliably filled up to immediately behind the steel pipe expansion lock bolt.

In the lock bolt structure of the present invention, the joint is provided with another annular sealing member that liquid-tightly seals the joint from the outside by pressing the front portion of the hollow lock bolt and the rear portion of the joint sleeve in the screwing-in direction. It is characterized by being attached to a sleeve.
According to this, the gap between the steel tube expansion lock bolt and the joint sleeve is liquid-tightly sealed with an annular seal material, and the gap between the hollow lock bolt and the joint sleeve is liquid-tightly sealed with another annular seal material. Therefore, the water injection introduction space of the hollow rock bolt itself can be used as a water injection passage for pressurized water injection into the steel pipe expansion type rock bolt. Moreover, since pressurized water injection can be performed without using a water injection pipe, the work of inserting and removing the water injection pipe can be eliminated, and the construction process can be made efficient.

The lock bolt structure of the present invention is characterized in that all threading mechanisms to be screwed are left-hand screw mechanisms.
According to this, the liquid-tight sealing of the annular seal member or the like can be reliably performed simply by rotating the hollow lock bolt protruding outside the opening of the drilled hole in the tightening direction of the left-handed screw. In other words, when the hollow lock bolt is originally a drilling rod, the drilling machine rotates counterclockwise in the forward direction, so the hollow lock bolt becomes a left-handed hollow lockbolt. Then, by rotating the hollow lock bolt in the tightening direction of the left-hand thread, the steel tube expansion type lock bolt and the joint sleeve are further tightened without loosening, and the annular seal member etc. are pressed in the screw-in direction. Therefore, a highly liquid-tight sealing state can be easily obtained.

The lock bolt structure of the present invention is characterized in that the hollow lock bolt is a rope screw.
According to this, the hollow rock bolt can be smoothly inserted into the drilled hole, and the adhesion of the fixing material to the hollow rock bolt can be improved. It is possible to increase the anchoring force to the pore wall.

A rock reinforcement structure of the present invention is a rock reinforcement structure comprising the rock bolt structure of the present invention, wherein the steel pipe expansion rock bolt, the joint sleeve, and the hollow rock bolt are arranged in order from the deep side of the borehole in the rock. is arranged, wherein the steel tube expansion rock bolt is frictionally fixed to the hole wall of the drill hole in an expanded state, and between the hole wall of the drill hole and the outer surface of the hollow rock bolt and the outer surface of the joint sleeve, A fixing material is filled and solidified.
According to this, the friction fixation of the expanded steel pipe expansion rock bolt on the inner side of the drilling and the fixation between the hole wall of the drilling and the outer surface of the hollow rock bolt and the outer surface of the joint sleeve on the mouth side of the drilling. By both fixing the material, the rock bolt structure can be reliably fixed to the natural ground over a long length, and the natural ground can be reinforced.

The joint sleeve of the present invention includes a steel tube expansion lock bolt having a closed front end and a threaded portion having a water inlet at the rear end, and a water inlet space provided inside along the axial direction. A joint sleeve that connects with a hollow lock bolt for fixing a fixing material, communicates in the axial direction, and has a threaded portion formed at the front portion that can be screwed into the threaded portion of the steel tube expansion type lock bolt. The front portion of the hollow lock bolt can be fixed to the rear portion, and an annular seal that liquid-tightly seals with the outside by pressing the screwing portion and the screwed portion in the screwing direction. It is characterized by having a material installed.
According to this, when a rock bolt structure composed of a steel pipe expansion type rock bolt, a hollow rock bolt, and a joint sleeve is driven into a long length deep into the ground and fixed, the joint sleeve can be used to connect the rock bolt structure to the depth of the drilled hole. On the side, it can be fixed by friction fixing in the expanded state of the steel pipe expansion type rock bolt, and there is no need to inject to the deep layer of the ground and the inner side of the drilled hole using a fixing material with high fluidity. That is, even when a rock bolt structure is fixed over a long length to a ground with many cracks, there is a problem that the highly fluid fixing material escapes from the cracks and disappears before it solidifies. Therefore, the rock bolt structure can be reliably fixed to the ground over a long length by both the friction fixing and the fixing of the fixing material. In addition, it is possible to use a fixing material with low fluidity, such as hard-kneaded mortar, because it can be fixed by friction fixing in the expanded state of the steel pipe expansion type rock bolt on the back side of the drilled hole in the ground. The diversity of possible fixing materials can be increased. In addition, when pressurized water is injected into the inside of the steel pipe expansion lock bolt using the water injection space of the hollow lock bolt and the water inlet of the steel pipe expansion lock bolt to make it expand, the liquid of the annular seal material of the joint sleeve Due to the sealing, it is possible to reliably prevent the injected water from leaking from the gap between the threaded portion of the joint sleeve and the threaded portion of the steel pipe expansion lock bolt. It is possible to increase the certainty of pressurized water injection to the steel pipe expansion rock bolt and expansion deformation.

The water injection structure of the present invention is a water injection structure screwed to a steel pipe expansion lock bolt having a threaded portion having a closed front end and a water injection port at the rear end. a hollow lock bolt, a water injection pipe inserted along the axial direction into the interior of the hollow lock bolt, and a threaded portion that communicates with the axial direction and is screwed with the threaded portion is formed at the front. , and a joint sleeve to which the front part of the hollow lock bolt is fixed at the rear part, and the front part of the water injection pipe is detachably attached to the connection part provided inside the screwed part of the joint sleeve on the rear side. A discharge hole connected between the hole wall of the bore hole in the natural ground and the outer surface of the hollow rock bolt and the outer surface of the joint sleeve, through which a fixing material can be injected, is positioned rearward of the connection portion of the joint sleeve. or the peripheral wall of the hollow lock bolt, and is liquid-tightly sealed from the outside by pressing the threaded portion and the threaded portion in the threading direction. is installed on the joint sleeve.
According to this, when a rock bolt structure composed of a steel pipe expansion type rock bolt, a hollow rock bolt, and a joint sleeve is driven into a long length deep into the ground and fixed, the joint sleeve can be used to connect the rock bolt structure to the depth of the drilled hole. On the side, it can be fixed by friction fixing in the expanded state of the steel pipe expansion type rock bolt, and there is no need to inject to the deep layer of the ground and the inner side of the drilled hole using a fixing material with high fluidity. That is, even when a rock bolt structure is fixed over a long length to a ground with many cracks, there is a problem that the highly fluid fixing material escapes from the cracks and disappears before it solidifies. Therefore, the rock bolt structure can be reliably fixed to the ground over a long length by both the friction fixing and the fixing of the fixing material. In addition, it is possible to use a fixing material with low fluidity, such as hard-kneaded mortar, because it can be fixed by friction fixing in the expanded state of the steel pipe expansion type rock bolt on the back side of the drilled hole in the ground. The diversity of possible fixing materials can be increased. In addition, when pressurized water is injected into the inside of the steel pipe expansion lock bolt using the water injection space of the hollow lock bolt and the water inlet of the steel pipe expansion lock bolt to make it expand, the liquid of the annular seal material of the joint sleeve Due to the sealing, it is possible to reliably prevent the injected water from leaking from the gap between the threaded portion of the joint sleeve and the threaded portion of the steel pipe expansion lock bolt. It is possible to increase the certainty of pressurized water injection to the steel pipe expansion rock bolt and expansion deformation. In addition, by forming a discharge hole through which the fixing material can be injected between the hole wall and the outer surface of the drilled hole in the ground in the joint sleeve or the hollow rock bolt arranged on the mouth side of the drilled hole, of the fixing material can be suppressed. In addition, by using the water injection structure in which the front portion of the water injection pipe is connected to the joint sleeve, it is possible to facilitate pressurized water injection when expanding the steel pipe expansion lock bolt.

In the construction method of the rock bolt structure of the present invention, a steel pipe expansion rock bolt having a screwed portion having a closed front end and a water inlet at the rear end is inserted into a hole in the ground in a non-expanded state. The front portion of a hollow lock bolt for fixing the fixing material, which communicates with the first step in the axial direction, has a threaded portion formed in the front portion, and has a water supply introduction space provided therein along the axial direction, is located in the rear portion. Using a fixed joint sleeve, the threaded portion of the joint sleeve is screwed to the threaded portion of the steel tube expansion lock bolt, and the annular seal member installed on the joint sleeve is screwed in the screwing direction. a second step of pressing against the annular seal material to liquid-tightly seal it with the outside, and moving the steel pipe expansion rock bolt to the back of the hole; a third step of pressurizing and pouring water into the steel pipe expansion rock bolt to expand the steel pipe expansion rock bolt and frictionally fix it to the hole wall of the bore; A fourth step of injecting and filling a fixing material between the outer surface and the hole wall of the perforation and solidifying the fixing material is provided.
According to this, when a rock bolt structure composed of a steel pipe expansion type rock bolt, a hollow rock bolt, and a joint sleeve is driven into a long length deep into the ground and fixed, the joint sleeve can be used to connect the rock bolt structure to the depth of the drilled hole. On the side, it can be fixed by friction fixing in the expanded state of the steel pipe expansion type rock bolt, and there is no need to inject to the deep layer of the ground and the inner side of the drilled hole using a fixing material with high fluidity. That is, even when a rock bolt structure is fixed over a long length to a ground with many cracks, there is a problem that the highly fluid fixing material escapes from the cracks and disappears before it solidifies. Therefore, the rock bolt structure can be reliably fixed to the ground over a long length by both the friction fixing and the fixing of the fixing material. In addition, it is possible to use a fixing material with low fluidity, such as hard-kneaded mortar, because it can be fixed by friction fixing in the expanded state of the steel pipe expansion type rock bolt on the back side of the drilled hole in the ground. The diversity of possible fixing materials can be increased. In addition, when pressurized water is injected into the inside of the steel pipe expansion lock bolt using the water injection space of the hollow lock bolt and the water inlet of the steel pipe expansion lock bolt to make it expand, the liquid of the annular seal material of the joint sleeve Due to the sealing, it is possible to reliably prevent the injected water from leaking from the gap between the threaded portion of the joint sleeve and the threaded portion of the steel pipe expansion lock bolt. It is possible to increase the certainty of pressurized water injection to the steel pipe expansion rock bolt and expansion deformation.

ADVANTAGE OF THE INVENTION According to this invention, a rock bolt structure can be reliably fixed to the natural ground over a long length even if it has many cracks.

1 is an exploded perspective view of a rock bolt structure and a water injection pipe of a first embodiment according to the present invention; FIG. FIG. 4 is a partial vertical cross-sectional view showing a water injection pipe connected to the lock bolt structure of the first embodiment; The cross-sectional perspective view of the joint sleeve in the rock bolt structure of 1st Embodiment. (a) is a front view of the state where the water injection pipe was connected to the rock bolt structure of 1st Embodiment, (b) is the longitudinal cross-sectional view. (a) is a front view of the inflated state of the lock bolt structure of 1st Embodiment, (b) is the longitudinal cross-sectional view. (a) is a cross-sectional explanatory view for explaining the screwing of the water injection structure in which the hollow rock bolt and the water injection pipe are connected to the joint sleeve in the first embodiment and the steel pipe expansion rock bolt, and (b) is the figure (a). (c) is a cross-sectional explanatory view for explaining pressurized water injection from the water injection structure to the inside of the steel pipe expansion rock bolt, and (c) is the rock bolt structure of the first embodiment in which the water injection pipe is pulled out and is in an expanded state. Cross-sectional explanatory drawing of this. (a) to (d) are process explanatory diagrams for explaining the construction process of the rock bolt structure of the first embodiment. FIG. 4 is a transverse explanatory view of a tunnel in which the rock bolt structure of the first embodiment is driven; FIG. 5 is an exploded perspective view of a rock bolt structure and a water injection pipe of a second embodiment according to the present invention; The cross-sectional perspective view of the joint sleeve in the lock bolt structure of 2nd Embodiment. (a) is a cross-sectional explanatory view for explaining screwing between a water injection structure in which a hollow rock bolt and a water injection pipe are connected to a joint sleeve in the second embodiment and a steel pipe expansion rock bolt; (c) is a second embodiment of the rock bolt structure in which the water injection pipe has been pulled out and is in an expanded state. Cross-sectional explanatory drawing of this. The disassembled perspective view of the rock bolt structure of 3rd Embodiment by this invention, and a water injection pipe. The cross-sectional perspective view of the joint sleeve in the lock bolt structure of 3rd Embodiment. (a) is a cross-sectional explanatory view for explaining screwing between a joint sleeve to which a hollow lock bolt is connected and a steel pipe expansion lock bolt in the third embodiment, and (b) is the inside of the steel pipe expansion lock bolt in the third embodiment. FIG. 11C is a cross-sectional explanatory view for explaining pressurized water injection into the body, and (c) is a cross-sectional explanatory view of the rock bolt structure of the third embodiment in an expanded state;

[Rock bolt structure of the first embodiment]
As shown in FIGS. 1 to 6, a rock bolt structure 1 of a first embodiment according to the present invention comprises a steel tube expansion type rock bolt 2 that expands when pressurized water is injected into the inside, and a hollow rock bolt for fixing a fixing material. 3 and a joint sleeve 4 that connects the steel tube expansion lock bolt 2 and the hollow lock bolt 3.

The steel tube expansion type lock bolt 2 is formed by pressurizing and pouring water into the inside from a non-expanded state in which the base body 21 formed by crushing and rounding the material steel tube from the outside over the entire length is folded into a substantially C-shaped cross section, and is formed into a substantially cylindrical shape. A front end sleeve 22 and a rear end sleeve 23 for restricting the expansion of the base body 21 are fitted and fixed to the front and rear ends of the base body 21, respectively (see FIG. 5). It is

A welded portion 24 that closes the front end of the steel tube expansion lock bolt 2 is provided on the inner peripheral side of the front end sleeve 22 near the front end. The welded portion 24 is build-up welded on the inner periphery of the front end sleeve 22 so as to close the space inside the base 21 of the steel pipe expansion lock bolt 2 and to fix the base 21 and the front end sleeve 22 . In the illustrated example, welding is used to block the space inside the base body 21 of the steel pipe expansion lock bolt 2, but instead of the welded part 24, a cap that can withstand pressurized water injection can be used to close the space. I do not care. In this case, the cap is also good as a cap that is fixed with a strength that can be released by performing pressurized water injection with increased water pressure after the steel pipe expansion lock bolt 2 is inflated by pressurized water injection, As a result, the cap is released by pressurized water injection with increased water pressure after the expansion of the steel pipe expansion rock bolt 2, and even if the perforation 101 of the natural ground 100 is not facing upward or obliquely upward, such as sideways, regardless of the direction of the perforation 101. In addition, water can be drained from the inside of the steel pipe expansion lock bolt 2 .

A hollow male threaded portion 25 corresponding to a screwed portion is arranged on the rear side of the rear end sleeve 23 and is fixed to the rear end sleeve 23 . It is configured to be A hollow portion 251 of the male threaded portion 25 corresponding to the water inlet of the threaded portion communicates with the inside of the base 21 of the steel pipe expansion lock bolt 2 , and the base 21 of the steel pipe expansion lock bolt 2 is connected through the hollow portion 251 . It is possible to inject pressurized water inside. Further, the male threaded portion 25 constitutes a left-handed screw mechanism whose tightening direction is counterclockwise.

The hollow lock bolt 3 fixed by the fixing material 10 is a rope screw type hollow lock bolt 3 having a rope male threaded portion 32 formed on a peripheral wall 31, and the rope male threaded portion 32 is a left-handed screw mechanism whose tightening direction is counterclockwise. is configured. The hollow lock bolt 3 is provided with a hollow portion 33 corresponding to the water injection introduction space along the axial direction inside the hollow lock bolt 3 . The water injection pipe 5 can be inserted along the axial direction of. In addition, a fixing material is provided on the peripheral wall 31 of the hollow rock bolt 3 between the hole wall 102 of the bore 101 of the ground 100 and the outer surface of the hollow rock bolt 3 or the outer surface of the joint sleeve 4 as necessary. It is also possible to form a discharge hole through which 10 can be injected.

The joint sleeve 4 has a substantially cylindrical shape that communicates with the joint sleeve 4 in the axial direction. The female threaded portion 41 can be screwed into the male threaded portion 25 corresponding to the portion to be screwed at the rear end of the steel pipe expansion lock bolt 2, and constitutes a left-handed screw mechanism. Further, the joint sleeve 4 is provided with an annular sealing material that liquid-tightly seals against the outside by pressing the threaded portion of the joint sleeve 4 and the threaded portion of the steel tube expansion lock bolt 2 in the threading direction. 42 is installed, and in the first embodiment, the annular seal member 42 is pressed by the rear end portion of the male threaded portion 25 of the steel pipe expansion lock bolt 2 screwed into the root of the female threaded portion 41 of the joint sleeve 4. It is furnished. The rear end surface of the male threaded portion 25 of the steel pipe expansion lock bolt 2 to be screwed into the annular seal member 42 is pressed against the annular seal member 42 so that the rear end surface of the male threaded portion 25 is pressed. Leakage of water to the outside from the threaded portion with the portion 41 is prevented.

A rope female threaded portion 43 that can be screwed with the rope male threaded portion 32 of the hollow lock bolt 3 is formed at the rear portion of the joint sleeve 4, and the rope female threaded portion 43 constitutes a left-handed screw mechanism. In this example, the front or front end portion of the hollow lock bolt 3 is connected to the joint by screwing the rope male thread portion 32 at the front portion or the front end portion of the hollow lock bolt 3 into the rope female thread portion 43 at the rear portion of the joint sleeve 4 . It is fixed to the rear part of the sleeve 4 .

On the rear side of the female threaded portion 41 corresponding to the threaded portion of the joint sleeve 4, a connecting portion to which the front portion of the water injection pipe 5 can be detachably connected is provided. A female threaded portion 44 corresponding to a connecting portion having a diameter smaller than that of 43 is formed, and the female threaded portion 44 is provided immediately behind the annular seal member 42 . A male threaded portion 51 is formed on the front portion or the front end portion of the water injection pipe 5 used in the first embodiment, and the male threaded portion 51 of the water injection pipe 5 inserted into the hollow portion 33 of the hollow lock bolt 3 is a female screw. It can be screwed onto the portion 44 . The front end face of the water injection pipe 5 screwed to the female threaded portion 44 abuts against the annular seal member 42 so as to be pressed, and the liquid-tight sealing due to this abutment prevents the threads between the male threaded portion 51 and the female threaded portion 44 during pressurized water injection. Water leakage to the outside from the joining portion is prevented. The male threaded portion 51 of the water injection pipe 5 and the female threaded portion 44 corresponding to the connecting portion also constitute a left-handed screw mechanism, and all screwing mechanisms screwed in the lock bolt structure 1 are left-handed screw mechanisms. there is

A hole portion 45 without a thread groove is provided between the rope female thread portion 43 of the joint sleeve 4 and the female thread portion 44 corresponding to the connecting portion. is also a cylindrical space with a large diameter. A discharge hole 47 is provided in the peripheral wall 46 behind the female threaded portion 44 corresponding to the connecting portion of the joint sleeve 4 so as to communicate the hole portion 45 with the outside of the joint sleeve 4 . The discharge hole 47 is formed so that the fixing material 10 can be injected between the hole wall 102 of the bore 101 of the ground 100 and the outer surface of the hollow rock bolt 3 or the outer surface of the joint sleeve 4 .

Before the rock bolt structure 1 of the first embodiment is driven into the natural ground 100, the hollow rock bolt 3, the joint sleeve 4, and the water injection pipe 5 do not have the steel pipe expansion type rock bolt 2. (See FIGS. 6(a), 6(b) and 7(b)). In this water injection structure, the front part of the hollow lock bolt 3 is fixed to the rear part of the joint sleeve 4 by screwing the rope male threaded part 32 to the rope female threaded part 43, and the hollow lock bolt 3 is axially inserted into the hollow lock bolt 3. The male threaded portion 51 of the water injection pipe 5 inserted along the line is detachably screwed and connected to the female screw portion 44 corresponding to the connecting portion of the joint sleeve 4, and the front end face of the water injection pipe 5 is pressed against the annular seal member 42. abut as

When the rock bolt structure 1 of the first embodiment is driven into the ground 100 to construct the ground reinforcement structure, for example, as shown in FIG. The non-expanded steel pipe expansion lock bolt 2 is inserted into the bore 101 formed in 1 (see FIG. 7(a)). A water injection structure in which the hollow lock bolt 3, the joint sleeve 4, and the water injection pipe 5 are integrated is used. The steel pipe expansion lock bolt 2 is screwed into the male threaded portion 25 corresponding to the threaded portion of the bolt 2, and moved to the depth of the hole 101 (FIGS. 7B, 6A, and 6B). reference).

At this time, by screwing the female threaded portion 41 of the joint sleeve 4 into the male threaded portion 25 of the steel tube expansion lock bolt 2 , the annular seal member 42 of the joint sleeve 4 is brought into contact with the rear end surface of the male threaded portion 25 of the steel tube expansion lock bolt 2 . is pressed in the direction of screwing in, and is liquid-tightly sealed so that water does not leak outside from the threaded portion between the male threaded portion 25 and the female threaded portion 41 . In this sealed state, the water injection pipe 5, the hollow portion 251 corresponding to the water injection port of the male thread portion 25, and the inside of the steel pipe expansion lock bolt 2 are communicated with each other.

After that, pressurized water injection is performed from the water injection pipe 5 inserted into the water injection introduction space of the water injection structure, and the water W is introduced into the steel pipe expansion lock bolt 2 through the hollow portion 251 corresponding to the water injection port of the male thread portion 25. By pressurizing and pouring water, the steel pipe expansion rock bolt 2 is expanded in the radial direction, and the base body 21 is brought into a substantially cylindrical expanded state, and the steel pipe expansion lock bolt 2 is frictionally fixed to the hole wall 102 of the bore 101 . After expanding the steel pipe expansion lock bolt 2 and completing friction fixation, the male threaded portion 51 of the water injection pipe 5 and the female threaded portion 44 of the joint sleeve 4 are unscrewed, the water injection pipe 5 is removed, and the water injection pipe 5 is removed. It is pulled out from the inside of the hollow lock bolt 3 (see FIGS. 7(c), 6(b), (c) and 5). In addition, the removed water injection pipe 5 is reused.

Then, the fixing material 10 such as mortar, urethane or silica resin is injected from the rear end of the hollow lock bolt 3, and the inside of the hollow lock bolt 3 is used as a flow path for the fixing material 10, and the discharge hole 47 of the joint sleeve 4 or the A fixing material 10 is injected and filled between the outer surface of the hollow lock bolt 3, the outer surface of the joint sleeve 4, and the hole wall 102 of the hole 101 through the discharge hole near the tip of the hollow lock bolt 3, thereby fixing. The material 10 is solidified to build a ground reinforcement structure (see FIGS. 7(d) and 6(c)). A washer 103 and a nut 104 are attached to the rear end of the hollow lock bolt 3 before or after the fixing material 10 is injected.

In the ground reinforcement structure constructed in this way, the steel pipe expansion type rock bolt 2, the joint sleeve 4, and the hollow rock bolt 3 are arranged in order from the back side of the bore 101 of the ground 100, and the steel pipe expansion on the back side of the bore 101 is arranged. The mold lock bolt 2 is frictionally fixed to the hole wall 102 of the perforation 101 in an expanded state, and the hole wall 102 of the perforation 101 and the outer surface of the hollow lock bolt 3 and the outer surface of the joint sleeve 4 at the mouth side of the perforation 101. The hollow lock bolt 3 and the joint sleeve 4 are fixed with the fixing material 10 filled and solidified between .

FIG. 8 shows an example of a natural ground reinforcement structure constructed by driving a plurality of rock bolt structures 1 radially into the natural ground 100 of a tunnel T. As shown in FIG. In this example of the ground reinforcement structure, in each rock bolt structure 1 that is radially driven, the expanded steel pipe expansion type rock bolt 2 is frictionally fixed to the hole wall in the expanded state, and the hollow rock bolt 3 and the joint A sleeve 4 is fixed with a solidified fixing material 10 .

According to the first embodiment, when the long rock bolt structure 1 is driven into the deep layer of the natural ground 100 and fixed, the expanded state of the steel pipe expansion type rock bolt 2 is friction fixed on the inner side of the bore 101. This eliminates the need to inject deep into the ground 100 and into the hole 101 using a fixing material with high fluidity. That is, even when fixing the rock bolt structure over a long length to the ground 100 with many cracks, there is a problem that the highly fluid fixing material escapes from the cracks and disappears before it solidifies. Therefore, the rock bolt structure 1 can be reliably fixed to the ground 100 over a long length by both the friction fixing and the fixing of the fixing material. Friction fixation of the expanded steel pipe expansion lock bolt 2 on the inner side of the hole 101, and the hole wall 102 of the hole 101, the outer surface of the hollow lock bolt 3, and the outer surface of the joint sleeve 4 on the mouth side of the hole 101. By both fixing the fixing material 10 in between, the rock bolt structure 1 can be reliably fixed to the natural ground 100 over a long length, and the natural ground 100 can be reinforced.

In addition, since the expansion state of the steel pipe expansion rock bolt 2 can be fixed by friction fixation on the far side of the drilled hole 101 of the natural ground 100, it is also possible to use a fixing material with low fluidity such as hard-kneaded mortar. It is possible to increase the variety of fixing materials 10 that can be used. Also, when pressurized water is injected into the inside of the steel pipe expansion lock bolt 2 using the water introduction space of the hollow lock bolt 3 and the water inlet of the steel pipe expansion lock bolt 2 to make the inside of the steel pipe expansion lock bolt 2 in an expanded state, the annular The liquid-tight sealing of the sealing material 42 can reliably prevent the injected water from leaking from the gap between the threaded portion of the joint sleeve 1 and the threaded portion of the steel tube expansion lock bolt 2. The reliability of pressurized water injection into the steel pipe expansion lock bolt 2 and expansion deformation of the steel pipe expansion lock bolt 2 can be enhanced.

Further, by making the threaded portion of the steel pipe expansion lock bolt 2 a male thread portion 25 and the threaded portion of the joint sleeve 4 a female thread portion 41, the steel pipe expansion lock bolt 2 and the joint sleeve 4 can be made to have high strength and stability. can be screwed together. Further, the annular seal member 42 at the base of the female threaded portion 41 of the joint sleeve 4 is pressed by the rear end portion of the male threaded portion 25 of the steel tube expansion lock bolt 2, so that the annular seal member 42 can be liquid-tightly sealed. .

In addition, by internally providing a female screw portion 44 corresponding to a connection portion to which the front portion of the water injection pipe 5 can be detachably connected to the rear side of the screwed portion of the joint sleeve 4, the rear side of the screwed portion of the joint sleeve 4 can be It is possible to introduce and connect the water injection pipe 5 to the side, and the reliability of pressurized water injection into the steel pipe expansion lock bolt 2 by the water injection pipe 5 and expansion deformation of the steel pipe expansion lock bolt 2 is further increased. be able to. Further, a discharge hole 47 or the like through which the fixing material 10 can be injected is formed in the joint sleeve 4 or the hollow rock bolt 3 arranged on the mouth side of the hole 101 between the hole wall 102 of the hole 101 of the ground 100 and the outer surface. By doing so, it is possible to suppress escape of the fixing material 10 to the inner side of the perforation 101 . In particular, when the discharge hole 47 into which the fixing material 10 can be injected is formed in the peripheral wall 46 of the joint sleeve 4, it becomes possible to fill the fixing material 10 even immediately behind the steel pipe expansion lock bolt 2 more reliably. .

In addition, by making all the screwing mechanisms in the lock bolt structure 1, including the screwing mechanism for the water injection pipe 5, a left-hand screw mechanism, the hollow lock bolt 3 protruding outside the hole opening can be tightened in a left-hand screw tightening direction. The liquid-tight sealing of the ring-shaped sealing material 42 can be ensured by simply rotating it. That is, when the hollow lock bolt 3 is originally a drilling rod, the left-handed hollow lock bolt 3 becomes a left-handed hollow lock bolt 3 because the left-handed rotation of the drilling machine is normal. In the case of a screw mechanism, by rotating the hollow lock bolt 3 in the left-hand tightening direction, the steel tube expansion lock bolt 2 and the joint sleeve 4 are further tightened without loosening, and the annular seal member 42 is screwed in. Since it is pressed in the direction, a highly liquid-tight sealing state can be easily obtained.

Further, by using the hollow lock bolt 3 as a rope screw, the hollow lock bolt 3 can be smoothly inserted into the perforation 101, and the adhesion of the fixing material 10 to the hollow lock bolt 3 can be enhanced. It is possible to increase the fixing force of the hollow lock bolt 3 or the fixing material 10 of the lock bolt structure 1 to the perforated hole wall 102 . In addition, by using a water injection structure in which the front portion of the water injection pipe 5 is connected to the joint sleeve 4, pressurized water injection work when expanding the steel pipe expansion lock bolt 3 can be facilitated.

[Rock bolt structure of the second embodiment]
As shown in FIGS. 9 to 11, a rock bolt structure 1a of a second embodiment according to the present invention includes a steel pipe expansion type rock bolt 2a that expands when pressurized water is injected into the inside thereof, and the same anchoring structure as in the first embodiment. It is composed of a hollow rock bolt 3 for fixing a material and a joint sleeve 4 a connecting the steel tube expansion rock bolt 2 a and the hollow rock bolt 3 . Incidentally, in the peripheral wall 31 of the hollow lock bolt 3, if necessary, a discharge hole into which the fixing material 10 can be injected may be formed as in the modified example of the first embodiment.

The steel tube expansion lock bolt 2a is composed of the same base 21, front end sleeve 22, rear end sleeve 23, and welded portion 24 as in the first embodiment, and corresponds to a threaded portion on the rear side of the rear end sleeve 23. A hollow female threaded portion 26a is arranged and fixed to the rear end sleeve 23, and the female threaded portion 26a is provided at the rear end of the steel tube expansion lock bolt 2a. As in the modification of the first embodiment, instead of the welded portion 24, the front end of the steel pipe expansion lock bolt 2a may be closed with a cap that can withstand pressurized water injection. A water injection hole 261a of the female threaded portion 26a corresponding to the water injection port of the threaded portion communicates with the inside of the base 21 of the steel pipe expansion lock bolt 2a, and the base 21 of the steel pipe expansion lock bolt 2 is fed through the water injection hole 261a. It is possible to inject pressurized water inside. Further, the female screw portion 26a constitutes a left-hand screw mechanism whose tightening direction is counterclockwise.

The joint sleeve 4a has a substantially cylindrical shape communicating in the axial direction. A male threaded portion 48a corresponding to a threaded portion is formed in the front portion of the joint sleeve 4a. 481a. The male threaded portion 48a can be screwed into the female threaded portion 26a corresponding to the threaded portion at the rear end of the steel tube expansion lock bolt 2a, thereby forming a left-handed screw mechanism.

The joint sleeve 4a is provided with an annular seal member 42a that is liquid-tightly sealed from the outside by pressing in the screw-in direction of the threaded portion of the joint sleeve 4a and the threaded portion of the steel tube expansion lock bolt 2a. In the second embodiment, an annular seal member 42a is pressed by the rear end of the female threaded portion 26a of the steel tube expansion lock bolt 2a screwed into the base of the male threaded portion 48a of the joint sleeve 4a. provided to be fitted. The rear end of the female threaded portion 26a of the steel tube expansion lock bolt 2a to be screwed into the annular seal member 42a is pressed against the annular seal member 42a. Leakage of water to the outside from the threaded portion with the male screw portion 48a is prevented.

A rope female threaded portion 43 that can be screwed with the rope male threaded portion 32 of the hollow lock bolt 3 is formed at the rear portion of the joint sleeve 4a, like the joint sleeve 4 of the first embodiment. On the rear side of the male threaded portion 48a corresponding to the threaded portion of the joint sleeve 4a, a female screw corresponding to a smaller diameter connection portion than the rope female threaded portion 43 is provided as a connection portion to which the front portion of the water injection pipe 5 can be detachably connected. A portion 44a is formed, and the female threaded portion 44a is located immediately behind the annular seal member 42a in the axial direction of the joint sleeve 4 and communicates with the hollow portion 481a of the male threaded portion 48a. The male threaded portion 51 of the water injection pipe 5 similar to that of the first embodiment is screwed into the female threaded portion 44a. The male threaded portion 51 of the water injection pipe 5 and the female threaded portion 44a corresponding to the connection portion also constitute a left-handed screw mechanism, and all screwing mechanisms screwed by the lock bolt structure 1a are left-handed screw mechanisms. there is

A hole portion 45 similar to that in the first embodiment is provided between the rope female thread portion 43 of the joint sleeve 4a and the female thread portion 44a corresponding to the connection portion. A peripheral wall 46 on the rear side of the portion 44 a is provided with a discharge hole 47 similar to that of the first embodiment so as to communicate the hole portion 45 with the outside of the joint sleeve 4 .

At the stage before the rock bolt structure 1a of the second embodiment is driven into the natural ground 100, the hollow rock bolt 3 and the joint are installed without the steel pipe expansion type rock bolt 2a, as in the first embodiment. It is preferable to construct a water injection structure in which the sleeve 4a and the water injection pipe 5 are integrated (see FIGS. 11(a), (b), and FIG. 7). In this water injection structure, the front portion of the hollow lock bolt 3 is fixed to the rear portion of the joint sleeve 4a by screwing the rope male thread portion 32 to the rope female thread portion 43, and an axial The male threaded portion 51 of the water injection pipe 5 inserted along the joint sleeve 4a is detachably screwed and connected to the female threaded portion 44a corresponding to the connecting portion of the joint sleeve 4a.

When the rock bolt structure 1 of the second embodiment is driven into the ground 100 to construct a ground reinforcement structure, the perforations 101 formed in the ground 100 in a required direction, such as obliquely upward, are not A water injection structure in which a steel pipe expansion lock bolt 2 in an expanded state is inserted, a hollow lock bolt 3, a joint sleeve 4a, and a water injection pipe 5 are integrated, and a threaded portion of the joint sleeve 4a of the water injection structure is used. The male threaded portion 48a corresponding to is screwed into the female threaded portion 26a corresponding to the threaded portion of the steel pipe expansion lock bolt 2a, and the steel pipe expansion lock bolt 2 is moved to the depth of the hole 101 (Fig. 7 (b ), see FIGS. 11(a) and (b)).

At this time, by screwing the male threaded portion 48a of the joint sleeve 4a into the female threaded portion 26a of the steel tube expansion lock bolt 2a, the annular seal member 42a of the joint sleeve 4a engages the rear end of the female threaded portion 26a of the steel tube expansion lock bolt 2a. It is pressed in the direction of screwing into the part, and is liquid-tightly sealed so that water does not leak to the outside from the threaded portion between the female threaded part 26a and the male threaded part 48a. In this sealed state, the water injection pipe 5, the hollow portion 481a of the male threaded portion 48a, the water injection hole 261a of the female threaded portion 26a, and the inside of the steel pipe expansion lock bolt 2 are communicated with each other.

After that, similarly to the first embodiment, water W is pressurized and injected from the water injection pipe 5 inserted into the water injection introduction space of the water injection structure, and the steel pipe expansion lock bolt 2a is injected through the water injection hole 261a of the female thread portion 26a. By pressurizing and pouring water into the interior of the steel pipe expansion lock bolt 2a, the steel pipe expansion lock bolt 2a is expanded in the radial direction, and the base body 21 is brought into a substantially cylindrical expansion state, and the steel pipe expansion lock bolt 2 is frictionally fixed to the hole wall 102 of the perforation 101. do. After expanding the steel pipe expansion lock bolt 2a and completing the friction fixation, the male threaded portion 51 of the water injection pipe 5 and the female threaded portion 44a of the joint sleeve 4a are unscrewed, the water injection pipe 5 is removed, and the water injection pipe 5 is removed. Pull out from the inside of the hollow lock bolt 3 (see FIGS. 7(c), 11(b) and (c)). In addition, the removed water injection pipe 5 is reused.

Then, similarly to the first embodiment, the fixing material 10 such as mortar, urethane, or silica resin is injected from the rear end of the hollow rock bolt 3, and the inside of the hollow rock bolt 3 is used as a flow path for the fixing material 10. The fixing material 10 is inserted between the outer surface of the hollow lock bolt 3 and the outer surface of the joint sleeve 4a and the hole wall 102 of the hole 101 through the discharge hole 47 of the joint sleeve 4a or the discharge hole near the tip of the hollow lock bolt 3. is injected and filled, and the fixing material 10 is solidified to construct the ground reinforcement structure (see FIGS. 7(d) and 11(c)).

According to the second embodiment, the threaded portion of the steel pipe expansion lock bolt 2a is the female thread portion 26a, and the threaded portion of the joint sleeve 4a is the male thread portion 48a. can be screwed together with high strength and stability. Further, the ring-shaped seal member 42a at the root of the male threaded portion 48a of the joint sleeve 4a is pressed by the rear end portion of the female threaded portion 26a of the steel tube expansion lock bolt 2a, so that the liquid-tight seal of the ring-shaped seal member 42a can be reliably performed. . In addition, corresponding effects can be obtained from a configuration corresponding to the first embodiment.

[Rock bolt structure of the third embodiment]
As shown in FIGS. 12 to 14, the rock bolt structure 1b of the third embodiment according to the present invention includes the same steel pipe expansion rock bolt 2 as in the first embodiment, and a hollow rock bolt 3b for fixing the fixing material. , a joint sleeve 4b connecting the steel tube expansion lock bolt 2 and the hollow lock bolt 3b. As in the modification of the first embodiment, instead of the welded portion 24, the front end of the steel pipe expansion lock bolt 2 may be closed with a cap that can withstand pressurized water injection.

The hollow lock bolt 3b fixed by the fixing material 10 has the same basic configuration as the hollow lock bolt 3 of the first embodiment, and is composed of a peripheral wall 31, a rope male screw portion 32, and a hollow portion 33. A fixing material injection pipe 34b is attached along the axial direction and attached to the outside of the peripheral wall 31 with a string or wire (not shown).

The joint sleeve 4b has a substantially cylindrical shape that communicates with the joint sleeve 4b in the axial direction. The female threaded portion 41b can be screwed into the male threaded portion 25 corresponding to the threaded portion at the rear end of the steel tube expansion lock bolt 2, thereby forming a left-handed screw mechanism. The joint sleeve 4b is provided with an annular seal member 42b that is liquid-tightly sealed from the outside by pressing in the screwing direction of the threaded portion of the joint sleeve 4b and the threaded portion of the steel tube expansion lock bolt 2. In the third embodiment, an annular seal member 42b pressed by the rear end portion of the male threaded portion 25 of the steel pipe expansion lock bolt 2 screwed into the base of the female threaded portion 41b of the joint sleeve 4b is provided. It is provided. The rear end surface of the male threaded portion 25 of the steel pipe expansion lock bolt 2 to be screwed into the annular seal member 42b is pressed against the annular seal member 42b so that the rear end surface of the male threaded portion 25 is pressed. Leakage of water to the outside from the threaded portion with the portion 41b is prevented.

At the rear portion of the joint sleeve 4b, similarly to the first embodiment, a rope female thread portion 43b that can be screwed with the rope male thread portion 32 of the hollow lock bolt 3b is formed, and the rope female thread portion 43b constitutes a left-hand screw mechanism. is doing.

Further, another annular seal member 491b is attached to the joint sleeve 4b for liquid-tight sealing with the outside by pressing the front portion of the hollow lock bolt 3b and the rear portion 4b of the joint sleeve in the screwing-in direction. In the third embodiment, an annular seal member 491b that is pressed by the tip of the hollow lock bolt 3b that is screwed into the joint sleeve 4b is provided internally on the tip side of the female rope thread portion 43b of the joint sleeve 4b. The tip surface of the hollow lock bolt 3b is pressed against the annular seal member 491b, and the liquid-tight sealing by this contact prevents the external flow from the threaded portion between the rope male threaded portion 32 and the rope female threaded portion 43b during pressurized water injection. Water leakage is prevented. In addition, all screwing mechanisms screwed in the lock bolt structure 1b of the third embodiment are also left-handed screw mechanisms.

Between the annular seal member 42b and the annular seal member 491b, a hole portion 492b having a smaller diameter than both the outer diameter of the annular seal member 42b and the annular seal member 491b is provided. The seal member 42b and the annular seal member 491b are fixed with their movements restricted.

At the stage before the rock bolt structure 1 of the third embodiment is driven into the ground 100, the hollow rock bolt 3b attached with the fixing material injection pipe 34b does not have the steel pipe expansion type rock bolt 2. It is preferable to construct a water injection structure in which the joint sleeve 4b is integrated (see FIGS. 14(a) and 14(b)). In this water injection structure, the front portion of the hollow lock bolt 3b is fixed to the rear portion of the joint sleeve 4b by screwing the rope male thread portion 32 to the rope female thread portion 43b, and the tip surface of the hollow lock bolt 3b is the joint sleeve. It abuts so as to be pressed by the annular seal member 491b of 4b. Further, the tip opening of the fixing material injection pipe 34b is arranged at a position near the joint sleeve 4b and not reaching the joint sleeve 4b.

Then, when the rock bolt structure 1b of the third embodiment is driven into the natural ground 100 to construct the natural ground reinforcement structure, the rock bolt structure 1b is mounted on the natural ground 100 in a required direction such as obliquely upward as in the first embodiment. The unexpanded steel pipe expansion lock bolt 2 is inserted into the bore 101 formed in . A water injection structure in which the hollow lock bolt 3b to which the fixing material injection pipe 34b is attached and the joint sleeve 4b are integrated is used, and a female screw portion corresponding to the threaded portion of the joint sleeve 4b of the water injection structure is used. 41b is screwed into the male threaded portion 25 corresponding to the threaded portion of the steel pipe expansion lock bolt 2, and the steel pipe expansion lock bolt 2 is moved to the depth of the hole 101 (Fig. 7(b), Fig. 14 ( a), (b) reference).

At this time, by screwing the female threaded portion 41 b of the joint sleeve 4 b into the male threaded portion 25 of the steel tube expansion lock bolt 2 , the annular seal member 42 b of the joint sleeve 4 b contacts the rear end surface of the male threaded portion 25 of the steel tube expansion lock bolt 2 . is pressed in the direction of screwing in, and is liquid-tightly sealed so that water does not leak to the outside from the threaded portion between the male threaded portion 25 and the female threaded portion 41b. In this sealed state, the hollow portion 33 of the hollow lock bolt 3b corresponding to the water introduction space, the hole portion 492b, the hollow portion 251 corresponding to the water injection port of the male thread portion 25, and the interior of the steel pipe expansion lock bolt 2. are communicated.

After that, without using a water injection pipe, water W is directly injected under pressure from the hollow portion 33 of the water injection introduction space of the hollow lock bolt 3b of the water injection structure, and the hollow portion 251 corresponding to the water injection port of the male thread portion 25 is filled. By pressurizing and injecting water into the steel pipe expansion lock bolt 2 through the steel pipe expansion lock bolt 2, the steel pipe expansion lock bolt 2 is expanded in the radial direction, and the base body 21 is expanded into a substantially cylindrical shape, and the steel pipe expansion lock bolt 2 is perforated. It is frictionally fixed to the hole wall 102 of 101 . (See FIGS. 14(b) and (c)). In addition, in the third embodiment, the work for inserting and removing the water injection pipe is unnecessary.

Then, the fixing material 10 such as mortar, urethane or silica resin is injected from the fixing material injection pipe 34b, and the fixing material is injected between the outer surface of the hollow lock bolt 3b, the outer surface of the joint sleeve 4b and the hole wall 102 of the perforation 101. 10 is injected and filled, and the fixing material 10 is solidified to construct the ground reinforcement structure (see FIG. 7(d) and FIG. 14(c)). A washer 103 and a nut 104 are attached to the rear end of the hollow lock bolt 3b before or after the fixing material 10 is injected.

According to the third embodiment, the gap between the steel tube expansion lock bolt 2 and the joint sleeve 4b is liquid-tightly sealed with the annular seal material 42b, and the gap between the hollow lock bolt 3b and the joint sleeve 4b is closed. It is possible to liquid-tightly seal with another annular seal material 491b, and the water injection introduction space itself of the hollow lock bolt 3b can be used as a water injection channel for pressurizing water injection into the steel pipe expansion lock bolt 2. . Moreover, since pressurized water injection can be performed without using a water injection pipe, the work of inserting and removing the water injection pipe can be eliminated, and the construction process can be made efficient. In addition, corresponding effects can be obtained from a configuration corresponding to the first embodiment.

[Scope of invention disclosed in this specification]
In addition to each invention, embodiment, and each example listed as an invention, the invention disclosed in this specification is specified by changing these partial contents to other contents disclosed in this specification within the applicable range or specified by adding other content disclosed in this specification to these contents, or specified by deleting these partial contents to the extent that partial effects can be obtained and making them a broader concept include those that The invention disclosed in this specification also includes the following contents and the following further modifications.

For example, as the hollow lock bolt in the lock bolt structure of the present invention, it is preferable to use a hollow lock bolt 3 in the form of a rope screw. Any suitable hollow lock bolt can be used.

In addition, the fixing structure of the front portion of the hollow lock bolt and the rear portion of the joint sleeve and the structure of the detachable connection portion between the joint sleeve and the water injection pipe in the present invention are preferably screwed structures of male and female threads. However, it is also possible to employ other fixing structures such as a hook structure in which one hook-like projection is engaged with the other locking groove, or a connecting portion structure.

Further, when constructing a rock reinforcement structure by driving the rock bolt structure of the present invention constructed using a water injection pipe into the natural ground, the water injection structure is used as in the first and second embodiments. However, it is preferable to use a construction method that uses a structure in which a non-expanded steel pipe expansion rock bolt is attached in advance to the tip side of the water injection structure, or a construction method that uses the rock bolt structure on the ground. It is also possible to use the construction method of inserting into the hole of the mountain and then connecting the water injection pipe to the joint sleeve of the rock bolt structure.

INDUSTRIAL APPLICABILITY The present invention can be used when rock reinforcement is performed using rock bolts.

DESCRIPTION OF SYMBOLS 1, 1a, 1b... Rock bolt structure 2, 2a... Steel pipe expansion type rock bolt 21... Base 22... Front end sleeve 23... Rear end sleeve 24... Welding part 25... Male screw part 251... Hollow part 26a... Female screw part 261a... Water injection Holes 3, 3b... Hollow lock bolt 31... Peripheral wall 32... Rope male screw part 33... Hollow part 34b... Fixing material injection pipe 4, 4a, 4b... Joint sleeve 41, 41b... Female screw part 42, 42a, 42b... Annular sealing material 43 , 43b... Rope female screw part 44, 44a... Female screw part 45... Hole part 46... Surrounding wall 47... Discharge hole 48a... Male screw part 481a... Hollow part 491b... Annular seal material 492b... Hole part 5... Water injection pipe 51... Male screw part 10... Fixing Material 100 Ground 101 Boring Hole 102 Hole Wall 103 Washer 104 Nut T Tunnel W Water

Claims (11)

a steel pipe expansion rock bolt having a closed front end and a threaded portion having a water inlet at the rear end;
a hollow rock bolt for fixing the fixing material, in which a space for introducing water is provided along the axial direction;
a joint sleeve communicating in the axial direction and having a threaded portion formed at the front,
The threaded portion of the joint sleeve and the threaded portion of the steel tube expansion lock bolt are screwed together, and the front portion of the hollow lock bolt and the rear portion of the joint sleeve are fixed,
The lock bolt structure is characterized in that an annular seal material is provided on the joint sleeve for liquid-tight sealing with the outside by pressing the threaded portion and the threaded portion in the screwing-in direction. body. The threaded portion of the steel pipe expansion lock bolt is a male threaded portion, and the threaded portion of the joint sleeve is a female threaded portion,
2. The rock bolt structure according to claim 1, wherein said annular seal member is provided at the base of said female threaded portion to be pressed by the rear end portion of said male threaded portion. The threaded portion of the steel pipe expansion lock bolt is a female threaded portion, and the threaded portion of the joint sleeve is a male threaded portion,
2. The rock bolt structure according to claim 1, wherein the annular seal member is provided at the base of the male threaded portion and is pressed by the rear end portion of the female threaded portion. A connection portion to which a front portion of a water injection pipe can be detachably connected is provided inside the joint sleeve on the rear side of the threaded portion,
a discharge hole through which a fixing material can be injected between the hole wall of the bore hole in the ground and the outer surface of the hollow rock bolt and the outer surface of the joint sleeve is located on the peripheral wall of the joint sleeve on the rear side of the connecting portion; Alternatively, the lock bolt structure according to any one of claims 1 to 3, which is formed on the peripheral wall of the hollow lock bolt. Another ring-shaped sealing material is attached to the joint sleeve for liquid-tight sealing with the outside by pressing the front part of the hollow lock bolt and the rear part of the joint sleeve in the screwing-in direction. The rock bolt structure according to any one of claims 1 to 3. 6. The lock bolt structure according to any one of claims 1 to 5, characterized in that all screwing mechanisms to be screwed are left-hand screw mechanisms. A rock bolt structure according to any one of claims 1 to 6, characterized in that said hollow rock bolt is a rope screw. A natural ground reinforcement structure comprising the rock bolt structure according to any one of claims 1 to 7,
The steel pipe expansion rock bolt, the joint sleeve, and the hollow rock bolt are arranged in order from the deep side of the drilled ground,
The steel pipe expansion rock bolt is frictionally fixed to the hole wall of the hole in an expanded state,
A ground reinforcement structure, wherein a fixing material is filled and solidified between the hole wall of the drill hole and the outer surface of the hollow rock bolt and the outer surface of the joint sleeve. A steel tube expansion lock bolt having a threaded portion with a closed front end and a water inlet at the rear end, and a hollow lock for fixing the fixing material with a water inlet space provided inside along the axial direction. A joint sleeve that connects the bolt,
communicated in the axial direction, the threaded portion formed at the front portion can be screwed to the threaded portion of the steel tube expansion lock bolt;
The front part of the hollow lock bolt can be fixed to the rear part,
A joint sleeve, wherein an annular seal member is installed to liquid-tightly seal with the outside by pressing the threaded portion and the threaded portion in a threading direction. A water injection structure screwed to a steel pipe expansion lock bolt having a screwed portion having a closed front end and a water injection port at the rear end,
a hollow rock bolt for fixing the fixing material;
a water injection pipe axially inserted into the hollow rock bolt;
a joint sleeve that communicates in the axial direction, has a threaded portion that is screwed to the threaded portion at the front portion, and has the front portion of the hollow lock bolt fixed at the rear portion;
A front portion of the water injection pipe is detachably connected to a connecting portion provided inside the threaded portion of the joint sleeve,
a discharge hole through which a fixing material can be injected between the hole wall of the bore hole in the ground and the outer surface of the hollow rock bolt and the outer surface of the joint sleeve is located on the peripheral wall of the joint sleeve on the rear side of the connecting portion; Or formed on the peripheral wall of the hollow lock bolt,
A water injection structure, wherein the joint sleeve is provided with an annular seal member that is liquid-tightly sealed from the outside by pressing the threaded portion and the threaded portion in the threading direction. . a first step of inserting, in a non-expanded state, a steel pipe expansion rock bolt having a threaded portion having a closed front end and a water inlet at the rear end into a hole in the natural ground;
A joint that communicates in the axial direction, has a threaded portion formed in the front portion, and has a hollow lock bolt for fixing the fixing material, in which a space for introducing water is provided along the axial direction, and the front portion of the hollow lock bolt is fixed to the rear portion. Using a sleeve, the threaded portion of the joint sleeve is screwed to the threaded portion of the steel tube expansion lock bolt, and the annular seal member installed on the joint sleeve is pressed in the threading direction to press the threaded portion. a second step of liquid-tightly sealing with the outside with an annular sealing material and moving the steel pipe expansion lock bolt to the depth of the hole;
a third step of injecting pressurized water into the inside of the steel pipe expansion rock bolt using the water introduction space and the water injection port to expand the steel pipe expansion rock bolt and frictionally fix it to the hole wall of the bore;
A lock characterized by comprising a fourth step of injecting and filling a fixing material between the outer surface of the hollow lock bolt and the outer surface of the joint sleeve and the hole wall of the perforation, and solidifying the fixing material. Construction method of bolt structure.

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