JP5401182B2 - How to install inflatable rock bolts - Google Patents

Description

  The present invention, for example, is used for tunnel support or fore-polling or for stable slopes, and in particular, a hollow pipe-shaped lock bolt body inserted into a drilling hole is expanded with a fluid such as water and fixed to the inner surface of the drilling hole. The present invention relates to a method for constructing an inflatable rock bolt.

  Conventionally, for example, as a support for a tunnel, a large number of rock bolts have been placed in the ground around the tunnel, or a rock bolt has been placed on the face as a fore-polling for reinforcing the previous ground during tunnel excavation. . Conventionally, as such a lock bolt, a solid rod shape made of deformed rebar is often used, and it is inserted into a drilling hole formed in a natural mountain and fixed with a cement-based or resin-based fixing material or the like. However, as an alternative to the lock bolt, a fixing material is used by expanding a hollow pipe-shaped lock bolt body with a fluid such as water in a state of being inserted into the drilling hole as in Patent Documents 1 to 3 below. There has been proposed an inflatable lock bolt that is pressure-bonded to the inner surface of the hole.

  FIG. 13 shows an example of the inflatable lock bolt 1 as described above. A front end sleeve 3 and a rear end sleeve 4 are provided on the outer periphery of both ends of a hollow pipe-shaped lock bolt main body 2 having a circular cross section. ing. The front end sleeve 3 is fitted and fixed to the outer periphery of the front end of the lock bolt main body 2 in the direction of insertion into a hole h to be described later, and the rear end sleeve 4 is rearward of the lock bolt main body 2 in the direction of insertion into the hole h. It is the structure which carried out fitting fixation to the edge part outer periphery of the side.

  The manufacturing method of the expandable lock bolt 1 as described above is appropriate, but FIG. 14 shows an example of this, and this example is a material pipe for forming the hollow pipe-shaped lock bolt main body 2 as shown in FIG. After using a metal tube 2 ′ having a circular cross section such as a steel tube as shown in (a), the metal tube 2 ′ is crushed in the diametrical direction as shown in FIG. Is rolled into a cylindrical shape so that both end portions in the width direction face each other to form a hollow pipe-shaped lock bolt main body 2 having a circular cross section as shown in FIG. Next, sleeves 3 and 4 are fitted to both ends in the axial direction of the lock bolt main body 2 as shown in FIG. 3D, and in this state, the sleeves 3 and 4 are each reduced in diameter and fixed by caulking.

  Both ends in the axial direction of the hollow pipe-shaped lock bolt body 2 are closed by the build-up welding W1 or the like in the sleeves 3 and 4 as shown in FIGS. 13 (d) and 14 (d), and the rear end. An injection hole 5 for injecting a fluid such as water into the lock bolt main body 2 is provided at a predetermined position on the peripheral surface of the sleeve 4 so as to penetrate the tube outside the lock bolt main body 2 inside the sleeve 4. ing.

  When the inflatable rock bolt 1 constructed as described above is driven in a ground such as a tunnel, it is first omitted from the drawing at a predetermined position of the ground G to be reinforced as shown in FIG. After forming a hole h such as a bore hole in advance with a drilling rod or drill with a drilling bit, an inflatable lock as shown in FIGS. 15 (b) and 16 (a). Insert the bolt 1. In the figure, reference numeral 6 denotes a bearing plate interposed between the open end of the hole h formed in the natural ground G and the rear end sleeve 4 of the lock bolt 1.

  Next, as shown in FIG. 15 (c), an injection pipe 8 is connected to the rear end sleeve 4 of the lock bolt 1 via an attachment 7 for injecting fluid, and the attachment 7 and the injection hole 5 are connected from the injection pipe 8. Then, a pressure fluid such as water is injected into the lock bolt main body 2. Then, the hollow pipe-shaped lock bolt main body 2 gradually expands over substantially the entire length as shown in FIG. 15 (d), and expands and expands into a substantially single cylindrical shape as shown in FIG. 16 (b). The bolt body 2 is held in a state of being pressed against the inner peripheral surface of the hole h. As a result, the lock bolt 1 is firmly fixed and fixed in the drilling hole h, and the natural ground G around the lock bolt 1 is consolidated by the lock bolt 1 so that the lock bolt functions as a support work. Or it can function as fore-polling.

  By the way, when the lock bolt 1 is inserted into the hole h, there is no problem if the hole h is straight and does not collapse. If there is a rough hole, a collapsed hole, etc., the insertion resistance will increase greatly, making it difficult to insert or making it impossible to insert. Therefore, in Patent Documents 2 and 3 below, a conical cone is provided at the tip of the lock bolt, but even if such a cone is provided, for example, a natural mountain where there is a lot of spring water and the inner surface of the drilling hole is likely to collapse. In many cases, it is very difficult to insert the lock bolt or it becomes impossible to insert the lock bolt.

JP-A-7-189598 JP-A-8-333999 JP-A-9-53397

  The present invention has been proposed in view of the above-mentioned problems.For example, even in a ground where there is a lot of spring water and the inner surface of the drilling hole is likely to collapse, an inflatable lock bolt is securely inserted into the drilling hole. An object of the present invention is to provide a method for constructing an inflatable rock bolt capable of expressing the function as a rock bolt.

In order to achieve the above object, the construction method of the inflatable rock bolt according to the present invention has the following configuration. That is, with the advancement of a drill bit connected to the tip of a casing pipe that can be expanded in the drill hole at the same time as making a drill hole for inserting the lock bolt in the ground where the inflatable lock bolt is to be constructed The excavating bit is inserted by being pulled into the drilling hole, and an inflatable lock bolt is inserted into the casing pipe to expand the lock bolt in a radial direction with a fluid such as water. The casing pipe is expanded in diameter, and the casing pipe expanded in diameter with the lock bolt is crimped and fixed to the inner surface of the hole.

  The construction method of the inflatable rock bolt according to the present invention includes a casing pipe capable of expanding the diameter of the drill hole at the same time as making a rock bolt insertion hole in the ground where the inflatable rock bolt is to be constructed as described above. Since it is inserted, for example, even in a drilling hole where there is a lot of spring water or the like and the hole wall tends to collapse, the casing pipe can suppress the collapse of the hole wall, and after drilling, An expandable lock bolt is inserted into the lock bolt, and the lock bolt is expanded in the radial direction with a fluid such as water. The casing pipe is expanded in accordance with the expansion operation of the lock bolt, and the lock pipe and the casing pipe expanded in diameter are cut. Since the inner surface of the hole is crimped and fixed, the function as the inflatable rock bolt can be satisfactorily placed on the ground and the function can be expressed.

  The above-mentioned casing pipe is inserted into the drilling hole at the same time when drilling a hole in the ground, and the inner surface of the drilling hole is prevented from collapsing due to spring water or the like, and into the casing pipe after drilling. When the lock bolt is further expanded in the radial direction, it is expanded in the radial direction, that is, expanded in diameter, and is plastically fixed to be fixed to the inner surface of the hole. Anything is acceptable. Specifically, for example, as the casing pipe, a material pipe that is formed in a tubular shape in advance can be formed by forming a slit extending in the generatrix direction at least at one place in the circumferential direction so that the diameter can be increased. Alternatively, the casing pipe can be expanded in diameter by rounding a flat plate-shaped material plate into a cylindrical shape, butting both circumferential ends thereof, and welding and joining a plurality of longitudinal portions of the butted portions. Can be used.

(A) is a front view which shows an example of the casing pipe used for the construction method of the inflatable rock bolt by this invention, (b) is the side view. (A) is a front view which shows the other example of the casing pipe used for the construction method of the inflatable rock bolt by this invention, (b) is the side view. (A)-(e) is explanatory drawing which shows an example of the process which constructs the inflatable rock bolt by this invention. (A) is a cross-sectional view of the state in which the inflatable lock bolt is inserted into the casing pipe, and (b) is the same as above in a state in which the lock bolt is expanded. (A) is a cross-sectional view of the state in which the inflatable lock bolt of the modified example is inserted into the casing pipe, and (b) is the same as above in a state in which the lock bolt is expanded. (A) is a cross-sectional view of a state in which an inflatable lock bolt of another modification is inserted into a casing pipe, and (b) is the same as above in a state in which the lock bolt is expanded. (A) is the longitudinal cross-sectional view of the example which applied the construction method of the expansion | swelling type rock bolt by this invention to the natural ground reinforcement work at the time of tunnel excavation, (b) is the cross-sectional view. (A) is a longitudinal cross-sectional view of the example which applied the construction method of the inflatable rock bolt by this invention to the reinforcement work of slopes, such as a cliff. The perspective view which shows an example of the equipment in the case of constructing an inflatable lock bolt in the hole back side of a drilling hole. Sectional drawing of the principal part which shows the connection structure by the sleeve for connection of the hollow rod for driving | running | working of the said equipment, and an inflatable rock bolt. Explanatory drawing which shows an example of the process which constructs an inflatable lock bolt in the hole back side of a drilling hole. Explanatory drawing which shows the construction example in the case of placing a casing pipe only in the hole back side of a drilling hole. (A) is a plan view of a conventional inflatable rock bolt, (b) is a front view thereof, (c) is a cc cross-sectional view in (b), (d) is a partially enlarged view of (c), (E) is ee sectional drawing in (d). (A)-(d) is explanatory drawing which shows an example of the manufacturing process of the said lock bolt. (A)-(d) is explanatory drawing which shows an example of the construction process of the conventional expansion type rock bolt. (A) is a cross-sectional view of the state where the lock bolt is inserted into the drilling hole, and (b) is the same view as above when the lock bolt is expanded.

  Hereinafter, the construction method of the expansion type rock bolt by the present invention is explained based on the embodiment shown in a figure. 1 and 2 show an example of a casing pipe used in the drainage method according to the present invention. The casing pipe 10 shown in FIG. 1 is at least a material pipe made of a steel pipe having a circular cross section formed in advance in a tubular shape. A slit-like cut groove 10a extending in the generatrix direction (axial direction) is formed at one circumferential direction so that the diameter can be increased as the inflatable lock bolt expands. In particular, in the case of the figure, the notch groove 10a is intermittently provided at a predetermined interval in the bus line direction so that the connecting portion 10b is left between the adjacent notch grooves 10a and 10a. . In the illustrated example, the connecting portions 10b are also left at both ends of the casing pipe 10, but the connecting portions 10b at both ends are not necessarily left. In the figure, the cut groove 10a is provided only at one place in the circumferential direction, but a plurality of the cut grooves 10a may be provided in the circumferential direction.

  Further, the casing pipe 10 shown in FIG. 2 is formed by rounding a rectangular plate in advance into a cylindrical shape, but abutting the circumferential end portions 10c with each other, and welding a plurality of longitudinal portions of the abutting portion by welding W2. It can be connected and expanded in diameter as the inflatable lock bolt expands. In addition, although the said embodiment comprised with the one raw material board in the circumferential direction, it comprised with several raw material boards in the circumferential direction, and face | matched the edge part of the adjacent raw material board to each other like the above. At the same time, a plurality of portions in the longitudinal direction of the butted portion may be welded and connected.

  The present invention constructs an inflatable rock bolt using the above-expandable casing pipe constructed as described above, and FIG. 3 shows an example of the construction process. In this example, the casing pipe 10 shown in FIG. 1 is used as the casing pipe, and the lock bolt 1 shown in FIG. 9 is used as the inflatable lock bolt as in the conventional example.

  In constructing the above-described inflatable lock bolt, first, similarly to the conventional example, a hole h such as a bore hole for inserting the lock bolt 1 is provided in the ground G and the like, and a casing pipe is provided in the hole h. Insert. FIG. 3 (a) shows an example, and a natural ground G is formed while rotating a drilling bit 12 attached to the tip of a hollow cylindrical drilling rod 11 together with the drilling rod 11 in a predetermined excavation direction. A hole h is formed in the ground G by being pushed in, and at the same time, the casing pipe 10 connected to the hole bit 12 via the casing shoe 13 is connected to the hole rod 11 and the hole bit. In accordance with the advancement of 12, they are drawn into the hole h together with them.

  Then, as shown in FIG. 3B, the drilling hole h is formed to a predetermined depth, and when the casing pipe 10 is inserted to a predetermined depth position in the drilling hole h, the drilling operation is finished. Next, the drilling rod 11 in the casing pipe 10 is pulled out and collected from the pipe 10 and repeatedly used for drilling work, and the drilling bit 12, the casing shoe 13 and the casing pipe 10 are placed in the drilling h. Let it remain. The means for forming the hole h as described above is not limited to the hole drilling bit 12 as described above, and various types of structures can be applied. For example, a known ring bit and center bit are used. In such a case, the center bit may be pulled out from the hole h together with the hole rod, collected, and reused so that the ring bit, the casing shoe, and the casing pipe remain in the hole h. The same applies to later-described embodiments.

  As shown in FIGS. 3C and 4A, the inflatable lock bolt 1 is inserted inside the casing pipe 10 remaining in the hole h as described above. At that time, a bearing plate 6 is interposed between the rear end sleeve 4 of the lock bolt 1 and the opening end of the drilling hole h as necessary, as in the conventional example. Next, as shown in FIG. 3 (d), an injection tube 8 is connected to the rear end sleeve 4 of the lock bolt 1 through an attachment 7 for fluid injection in the same manner as the conventional example, and the attachment 7 is connected to the injection tube 8 from the injection tube 8. A pressure fluid such as water is injected into the lock bolt main body 2 through the injection hole 5.

  Then, like the conventional example, the hollow pipe-shaped lock bolt body 2 gradually swells over almost the entire length in the longitudinal direction as shown in FIG. 3 (e), and expands into a substantially single cylindrical shape as shown in FIG. 4 (b). Accordingly, the casing pipe 10 is also expanded in the diameter increasing direction. At that time, the casing pipe 10 formed as shown in FIG. 1 has a connecting part 10b between adjacent cut grooves 10a and 10a broken to form a circular shape, and a plurality of cut grooves 10a are provided in the circumferential direction. In this case, the connecting portion 10b or the vicinity thereof extends in the circumferential direction, and the casing pipe 10 is also brought into pressure contact with the inner surface of the hole h together with the lock bolt body 2 while the diameter of the casing pipe 10 is increased. As a result, the expanded lock bolt body 2 is held in pressure contact with the inner peripheral surface of the hole h via the casing pipe 10 having an enlarged diameter, and the lock bolt 1 is firmly fixed and fixed in the hole h. At the same time, the natural ground G around the lock bolt 1 is consolidated by the lock bolt 1, and the function as the lock bolt can be expressed.

  After injecting the pressure fluid into the lock bolt body 2 as described above and bringing it into pressure contact with the inner surface of the drilling hole through the expanded casing pipe 10, the pressure fluid into the lock bolt body 2 is supplied. The injection is stopped and kept in that state, or the pressure fluid in the lock bolt body 2 is discharged from the injection hole 5. Alternatively, after discharging the pressure fluid, a solidified material such as mortar may be injected into the lock bolt body 2.

  As described above, the method for constructing the inflatable rock bolt according to the present invention is capable of expanding the diameter of the rock bolt h at the same time as making the rock bolt insertion hole h in the ground G where the lock bolt 1 is to be constructed. Since the casing pipe 10 is inserted, for example, the casing pipe 10 can suppress the collapse of the hole wall even in the hole h where there is a lot of spring water or the like and the hole wall is likely to collapse. After that, the inflatable lock bolt 1 is inserted into the casing pipe 10 to expand the lock bolt 1 in a radial direction with a fluid such as water, and the casing pipe is expanded in diameter, and the casing is expanded in diameter with the lock bolt. Since the pipe 10 is pressure-fixed to the inner surface of the drilling hole, even if there is a lot of spring water and the inner surface of the drilling hole is likely to collapse, an inflatable lock bolt is securely inserted into the drilling hole to lock the bolt. As It is possible to satisfactorily express functional.

  In the above embodiment, the casing pipe 10 having the configuration shown in FIG. 1 is used as the casing pipe 10 capable of expanding the diameter, but the casing pipe 10 having the configuration shown in FIG. 2 can also be used. Even in that case, the welded portion W2 is broken when the expandable lock bolt 1 is expanded, and the same effect as described above can be obtained. The material and configuration of the casing pipe 10 are not limited to those shown in FIGS. 1 and 2, and can be changed as appropriate. At least, the inner surface of the hole is broken by spring water or the like by inserting it into the hole h formed in the natural ground G. After drilling, insertion of the inflatable lock bolt 1 into the casing pipe 10 is allowed, and when the lock bolt 1 is further expanded in the radial direction, the casing pipe 10 What is necessary is just to be able to fix and fix in a state of expanding in the radial direction and in close contact with the inner surface of the hole.

  Moreover, although the said embodiment used the thing of the cross-sectional shape before expansion | swelling of the expansion | deployment type rock bolt 1 as shown in the said FIG. 4 (a), for example, FIG. 5 (a) or FIG. It is also possible to use one having such a cross-sectional shape. FIGS. 5B and 6B are cross-sectional views of the lock bolt 1 shown in FIGS. 5A and 6A during expansion. Other than the above, various types of cross-sectional lock bolts can be used.

  Furthermore, the construction method of the inflatable rock bolt according to the present invention can be applied to various grounds (including rocks), and a specific target thereof is, for example, when excavating a tunnel T as shown in FIG. The present invention can be suitably applied to a case where the front ground of the face mirror part 21 is reinforced (fore polling) or a pattern bolt as a support for the tunnel space T after tunnel excavation. In the figure, reference numeral 22 denotes sprayed concrete provided in the face mirror part 21, and 23 denotes a steel support laid on the inner peripheral surface of the tunnel space T after tunnel excavation.

  The present invention is not limited to the tunnel excavation work as described above, and can be applied to, for example, the case where a slope as shown in FIG. 8 is reinforced. In this case, there are cases where the casing pipe 10 and the lock bolt 1 are constructed in a substantially horizontal direction as shown in the figure, or in an inclined state so that the opening side of the drilling hole h is lower and higher than the back side of the hole. In this case, when the fluid such as water injected into the lock bolt main body 2 is discharged from the lock bolt main body after construction (after expansion), natural discharge becomes impossible. The fluid may be discharged from the mouth side of the lock bolt body 2 with a pump.

  Further, in the above embodiment, the inflatable rock bolt 1 is constructed over almost the entire length of the drilling hole h formed in the ground (including the above-mentioned rock mass and slope) as described above. It is also possible to lay the inflatable lock bolt 1 only on the part, for example, the hole back side, the opening side (mouth side) or the longitudinal middle part of the hole. For example, this is effective when the inflatable rock bolt 1 is constructed in a tunnel with a small cross section excavated in advance and then widened into a tunnel with a large cross section.

  FIG. 9 shows an example of equipment in the case where the inflatable lock bolt 1 is constructed only on the back side of the hole h. In the figure, 9 is for placing the inflatable lock bolt 1 on the back side of the hole. A hollow rod 41 for driving is a connecting sleeve for connecting the hollow rod 9 for driving and the inflatable lock bolt 1. The connecting sleeve 41 is fixed in advance to the rear end portion of the lock bolt main body 2 by welding or the like instead of the rear end sleeve 4 in FIG. 3, and the front end sleeve 3 similar to the above is attached to the front end portion of the lock bolt main body 2. The inflatable lock bolt 1 that is substantially the same as described above is configured by providing the.

  As shown in FIGS. 9 and 10, the driving hollow rod 9 has a female screw hole in which a male screw 9 a provided at one end thereof is formed at an end of the connecting sleeve 41 opposite to the lock bolt body 2. When the fluid is injected into the lock bolt main body 2 into the other end of the hollow rod 9, the hollow bolt 9 is connected to the lock bolt main body 2 via the connecting sleeve 41 by screwing into the 41a. A receiving portion 9b for connecting the fluid injection attachment (adapter) 7 is integrally provided, and a fluid injection hole 9c is provided in the receiving portion 9b.

  When the lock bolt 1 is inflated, the large-diameter portion 7a on one end side of the fluid injection attachment (adapter) 7 similar to the above is applied to the receiving portion 9b of the hollow rod 9 so as to cover the injection hole 9c. The above-mentioned injection pipe 8 or the like not shown in the figure is connected to the injection port 7b on the other end side of the attachment 7 to inject a fluid such as water. Then, the fluid that has flowed into the attachment 7 from the injection port 7 b flows into the connection sleeve 41 through the hollow rod 9 from the injection hole 9 c, and the small size provided in the partition 41 b in the connection sleeve 41. The lock bolt body 2 enters the lock bolt body 2 through the hole 41c and expands in the same manner as described above.

  Next, after constructing the inflatable rock bolt 1 from the tunnel inner surface Ta with a small cross-section, for example, excavated in advance toward the inside of the natural ground G, etc. In the case of widening, construction may be performed as follows. First, as shown in FIG. 11 (a), cutting is performed from the tunnel inner surface Ta having a small cross section toward the ground G using the drilling rod 11, the drilling bit 12, the casing shoe 13 and the like similar to those shown in FIG. Simultaneously with the formation of the hole h, the casing pipe 10 having the same configuration as described above is drawn into the hole h. Then, when the hole is drilled to a predetermined depth and the casing pipe 10 is drawn, the hole rod 11 is pulled out and collected.

  Next, in the casing pipe 10, as shown in FIG. 11 (b), the inflatable lock bolt 1 composed of the connecting sleeve 41, the lock bolt main body 2 and the tip sleeve 3, and the placing hollow rod 9. Insert while connected to each other. Then, the fluid injection attachment 7 is connected to the receiving portion 9b of the hollow rod 9 as shown in FIG. 11C, and a fluid such as water is injected from the injection pipe 8 connected to the injection port 7b of the attachment 7. Then, the lock bolt body 2 is expanded by pressurizing and injecting the fluid into the lock bolt body 2 via the attachment 7, the hollow rod 9 and the connecting sleeve 41.

  As the lock bolt expands, the casing pipe 10 positioned around the lock bolt main body 2 also expands in the diameter-expanding direction as shown in FIG. 11C, so that the casing formed as shown in FIG. In the pipe 10, the connecting portion 10b between the adjacent cut grooves 10a and 10a is broken and becomes a circular shape, and a plurality of the cut grooves 10a are provided in the circumferential direction as shown in FIG. Is connected to the inner surface of the drilling hole h together with the lock bolt body 2 while the casing pipe 10 is expanded in diameter by extending the connecting portion 10b or its vicinity in the circumferential direction. As a result, the lock bolt body 2 is held in pressure contact with the inner peripheral surface of the hole h through the casing pipe 10, and the lock bolt 1 is firmly fixed and fixed in the hole h. The surrounding natural ground G is consolidated by the lock bolt 1, and the function of the lock bolt 1 can be expressed well.

  After the lock bolt 1 and the casing pipe 10 have sufficiently expanded in diameter as described above, the attachment 7, the injection tube 8, and the hollow rod 9 are removed as shown in FIG. Next, when the operation in the small-section tunnel inner surface Ta in which the small-section tunnel inner surface Ta is located on the left side of FIG. By excavating the natural ground G, the tunnel space is expanded as shown in FIG. 11E. At that time, the casing pipe 10 at the excavation position may be removed while being crushed by the tunnel excavating machine. . In this case, the casing pipe 10 can be crushed by the excavating machine as described above unless an extremely thick steel pipe or the like is used. However, in some cases, a thin steel pipe, a soft metal pipe, or a synthetic resin pipe is used. Etc. may be used.

  As described above, in the present invention, the inflatable lock bolt 1 can be laid only on the back side of the drilling hole h formed in the natural ground G or the like. In this case, the length of the hollow rod 9 is appropriately set. If the length is set, the inflatable lock bolt 1 can be easily installed at a desired depth position of the hole h. Moreover, what is necessary is just to set the length of the said casing pipe 10 suitably according to the installation depth of the lock bolt 1. FIG.

  In the above embodiment, the casing pipe 10 is provided over almost the entire length in the length direction of the hole h. However, the casing pipe 10 may be provided only at a position where the lock bolt 1 is installed, particularly, a position where the lock bolt main body 2 expands. In the above-described embodiment, the inflatable lock bolt 1 is provided on the deep side of the hole h. However, the inflatable lock bolt 1 may be provided on the longitudinal intermediate position of the hole h or on the opening side of the hole h. In the case where it is provided at the intermediate position in the longitudinal direction of the hole h, the length of the hollow rod 9 may be adjusted according to the position of the hole h. What is necessary is just to use the lock bolt shown in the said FIGS. 3-6 and FIG. 13 without using.

  As described above, according to the construction method of the inflatable rock bolt according to the present invention, the lock bolt 1 is inserted into the casing pipe 10 in a state where the casing pipe 10 is inserted into the hole h formed in the natural ground G. For example, when installing on a natural ground where there is a lot of spring water and the hole wall of the drilling hole h is easy to collapse, the casing pipe 10 is used to prevent the rock wall from collapsing. In addition to being able to be inserted easily, the lock bolt is expanded and the casing is expanded in diameter, so that the lock pipe and the expanded casing pipe 10 can be easily fixed to the inner surface of the hole. Therefore, it is possible to apply the rock bolt to various grounds where there is spring water or collapse of the hole, and it can be effectively used industrially.

DESCRIPTION OF SYMBOLS 1 Expansion type rock bolt 2 Rock bolt main body 3 Front end sleeve 4 Rear end slave 5 Injection hole 6 Bearing plate 7 Attachment 8 Injection pipe 9 Hollow rod 10 Casing pipe 10a Cut groove 10b Connecting part 10c End part 11 Hole rod 12 Hole Bit 13 Casing shoe 21 Mirror face 22 Sprayed concrete 23 Support

Claims (3)

With the advancement of a drill bit connected to the tip of a casing pipe that can be expanded in the drill hole at the same time as making a drill hole for inserting a lock bolt in the ground where an inflatable lock bolt is to be constructed , The excavation bit is inserted by being pulled into the drilling hole, and an inflatable lock bolt is inserted into the casing pipe to expand the lock bolt in a radial direction with a fluid such as water, and the casing pipe. A method for constructing an inflatable lock bolt, wherein the diameter of the lock pipe and the casing pipe expanded in diameter are fixed to the inner surface of the hole.   The construction of the inflatable rock bolt according to claim 1, wherein the casing pipe can be expanded in diameter by forming a slit-like cut groove extending in the generatrix direction at least in one circumferential direction of a material pipe formed in a tubular shape in advance. Method.   The casing pipe is formed by rounding a flat plate-shaped material plate into a cylindrical shape, butting both ends in the circumferential direction, and welding and connecting a plurality of longitudinal portions of the butting portion so that the diameter can be increased. The construction method of the expansion type rock bolt of claim | item 1.

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