JP3842358B2 - Lock bolt cap - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lock bolt cap, and more particularly, to a lock bolt cap used in a full-adhesion lock bolt method in which a fixing material is injected into a pre-drilled borehole and then a bolt is driven.
[0002]
[Prior art]
Construction methods for full-adhesion lock bolts used in tunnels and slope protection works by the NATOM method (NATM construction method) are broadly divided into a pre-injection type full-adhesion type and a post-injection type full-adhesion type depending on the injection type. Of these, the pre-injection type full-surface adhesion type is a method in which cemented milk or mortar is filled into a bore hole drilled in a natural ground, and then a solid-type rock bolt is inserted. Depending on the type of fixing material, the pre-injection type full-adhesion type lock bolt is obtained by obliquely cutting the tip 1a of the bolt 1 as shown in FIG. 6, or the tip 1b of the bolt 1 as a pencil as shown in FIG. A sharpened sword tip is used.
[0003]
FIG. 8 is an explanatory diagram of a pre-injection-type full-adhesion-type lock bolt construction method, wherein 1 is a lock bolt, 2 is a natural ground, 3 is a tunnel, 4 is an inner wall of the tunnel, 5 is a bore hole, and 6 is a fixing material. First, a bore hole (cylindrical void) 5 having a predetermined depth is drilled from the inner wall 4 of the tunnel 3 excavated in the natural ground 2 to the inside of the rock. Next, a fixing material such as mortar or resin is injected or loaded into the bore hole 5 using an injection hose or the like, and then a lock bolt 1 whose tip is obliquely cut or sword processed (sword tip processing in FIG. 8) is inserted and driven. . In this state, if the fixing material 6 is hardened, the periphery of the hole wall of the lock bolt 1 and the bore hole 5 is integrally fixed, and is supported by a hard internal bedrock into which the tip of the lock bolt is driven. Collapse is prevented.
The rear end portion of the lock bolt 1 is threaded in advance, and a nut and a washer are applied as necessary.
[0004]
[Problems to be solved by the invention]
By the way, the conventional pre-injection type full adhesion type lock bolt has the following problems. The first problem is that a bolt steel material that has been cut to a predetermined length in advance must be finished as a lock bolt by subjecting the tip steel to oblique tip processing or tip tip processing at the factory, and it takes time to process the lock bolt. The second problem is that the bolt length change request cannot be handled on site.
Therefore, it is possible to use the steel material as a lock bolt only by cutting the bolt steel material to a predetermined length, that is, without performing oblique tip machining or tip machining, and easily change the bolt length. There is a need for some means to make this possible.
[0005]
In view of the above, an object of the present invention is to provide a lock bolt cap that can use a bolt steel material simply cut to a predetermined length as an excellent lock bolt.
Another object of the present invention is to provide a cap for a lock bolt in which one cap can be used for a plurality of bolt steel materials having different diameters.
Another object of the present invention is to provide a lock bolt cap that can prevent the lock bolt from falling even if the lock bolt is driven upward.
[0006]
[Means for Solving the Problems]
According to the present invention, there is provided a hollow bolt receiving portion inside a cap body having a pointed portion, and a step is formed in the bolt receiving portion to receive a lock bolt having a different diameter. This is achieved by a lock bolt cap provided with a first receiving portion and a fixing material introducing hole penetrating from the tip end surface to the bolt receiving portion . According to such a cap, it is possible to use the bolt steel material as a lock bolt simply by attaching a bolt steel material cut to a predetermined length to the cap, and therefore it is not necessary to carry out a tip oblique machining or a tip sword machining at a factory. In addition, it is possible to prepare a lock bolt by cutting steel on site according to the required bolt length and attaching a cap to this, so it is easy to respond to bolt length change requests etc. can do.
[0007]
Moreover, according to the present invention, since the first and second receiving portions are provided by forming one or more steps in the bolt receiving portion, the bolt steel material is inserted into the bolt receiving portion corresponding to the diameter of the bolt steel material. Thus, the cap and the bolt steel material can be integrated, and one cap can be used for a plurality of bolt steel materials having different diameters.
Furthermore, according to the present invention, since the frustoconical overhanging portion is hollowed out in the rear end portion of the cap body, the overhanging portion remains in the borehole hole wall even if the lock bolt is driven upward. It can be hooked to prevent the lock bolt from falling.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
(A) First Embodiment FIG. 1 is an explanatory view of a lock bolt cap according to a first embodiment of the present invention, FIG. 1 (a) is a plan view, and FIG. 1 (b) is FIG. 1 (a). It is b arrow line view.
The cap 11 includes a cap main body portion 12 and a pointed end portion 13. A cylindrical bolt receiving portion 14 having one end opened is formed in the cap body portion 12. The bolt receiving portion 14 has a stepped shape, and includes a first bolt receiving portion 14a having a small diameter and a second bolt receiving portion 14b having a large diameter. The first bolt receiving portion 14a is a portion that receives a small-diameter bolt steel material, and the second bolt receiving portion 14b is a portion that receives a large-diameter bolt steel material.
The pointed end portion 13 has a mountain-shaped shape. This is tip 13, four fixing material introduction hole 15a penetrating from tip surface to the bolt receiving portion 14, 15b, 15c, 15d are formed at intervals of 90 ^0.
The cap 11 is integrally formed of a highly rigid material such as plastic by molding.
[0009]
FIG. 2 is an explanatory view of an example of using the cap, and the cap shows a cross-sectional view. In the figure, 11 is a lock bolt cap, and 21 is a small-diameter bolt steel material having a certain pattern of irregularities formed on the entire surface. The diameter of the first bolt receiving portion 14 a of the cap 11 is slightly larger than the diameter of the bolt steel material 21.
In use, a bolt steel material 21 is prepared by cutting a deformed steel bar having a certain pattern of irregularities on the entire surface into a straight shape, and the bolt steel material 21 is inserted into the first bolt receiving portion 14a of the cap 11 (FIG. 2). (See dashed line). Thereby, the setting of the bolt steel material 21 is completed and a lock bolt is formed. In this process, if the insertion of the bolt steel material 21 is stopped at an appropriate position, a slight space SP is formed at the tip of the bolt steel material 21. When the lock bolt is inserted into the bore hole, the fixing material in the bore hole naturally enters the space SP through the fixing material introduction holes 15a to 15d to fill the space, and the cap 11 and the bolt steel material 21 are firmly integrated. To do. Further, when the space SP is filled with the fixing material, the end portion of the bolt steel material 21 and the space around it are eliminated, and the end portion of the steel material 21 that is simply cut is subjected to a rust prevention treatment. This rust prevention treatment is completed without any other trouble by utilizing the fact that the fixing material is introduced into the space SP from the fixing material introduction holes 15a, 15b, 15c, and 15d as the lock bolt is inserted into the bore hole. . A stopper may be provided at the insertion completion position in the first receiving portion 14a, and the insertion may be stopped when it hits the stopper.
The above is the case where the small-diameter bolt steel material 21 is attached to the cap 11, but when the large-diameter bolt steel material is attached to the cap 11, the bolt steel material is inserted into the second bolt receiving portion 14b.
[0010]
FIG. 3 is an explanatory diagram of a method for installing a rock bolt according to the present invention, wherein 11 is a cap, 21 is a bolt steel material, 51 is a natural ground, 52 is a borehole, and 53 is a fixing material.
First, a bore hole 52 having a predetermined depth is drilled in the natural ground 51. Next, a fixing material such as mortar, cement milk, or resin is injected or loaded into the bore hole 52 using an injection hose or the like. Thereafter, a lock bolt having the cap 11 attached to the bolt steel material 21 is inserted and driven into the bore hole. As the bolt is inserted, the fixing material 53 enters and fills the space SP from the fixing material introduction holes 15a to 15d provided at the tip of the cap, as shown by arrows, and the bolt steel material 21 and the cap 11 are firmly fixed and integrated. In addition, the gap in the cap is filled with the fixing material 53, and a fixing material filling state without a gap is obtained. By the above, the coupling | bonding degree between the bolt steel material 21 and the cap 11 can be strengthened, the situation where a space | gap remains in a bore hole can be prevented, and also the rust prevention effect can be acquired.
[0011]
As described above, according to the first embodiment, the bolt steel material can be used as a lock bolt only by attaching the bolt steel material cut to a predetermined length to the cap 11, and therefore, the tip end oblique machining and the tip end can be performed at the factory. There is no need to process the sword. In addition, it is possible to prepare steel bolts by cutting steel materials on site according to the required bolt length and attaching a cap to this, so it is possible to easily respond to bolt length change requests on site. be able to. Further, by providing a plurality of bolt receiving portions, one cap can be used for a plurality of bolt steel materials having different diameters.
[0012]
(B) In the above modification, the bolt receiving portion 14 is provided with the first and second bolt receiving portions 14a, 14b, but the cap is provided so as to receive only one type of diameter steel bar without providing a step. Can also be formed. Conversely, by providing two or more steps, the cap can be formed so as to accept steel bars having three or more types of diameters.
In the above description, the case where a deformed steel bar cut into a straight shape is used as the bolt steel material is described. Yes, the type of steel bar is not specified.
[0013]
(B) Second Embodiment FIG. 4 is an explanatory view of a lock bolt cap according to a second embodiment of the present invention. The same reference numerals are given to the same parts as those in the first embodiment of FIG. 4A is a plan view, FIG. 4B is a view taken in the direction of arrow b in FIG. 4A, and FIG. 4C is a cross-sectional view.
The second embodiment is different from the first embodiment in that (1) a protruding portion 31 is provided at the rear end of the cap 11, and (2) a step is not formed inside the cap main body 12, and a predetermined step is provided. The point is that a bolt receiving part 14 for receiving only a bolt steel material with a diameter is provided, and (3) the pointed part 13 is thinned. The point provided with the tip portion 13 and the fixing material introduction holes 15a to 15d is the same as in the first embodiment. The projecting portion 31 has a truncated cone shape in which the inside is hollowed out, and is formed in a large diameter so as to project from the end portion of the cap main body portion 12.
When the cap is used, as in the first embodiment (see FIG. 2), a bolt steel material obtained by cutting a steel bar into a straight shape is inserted into the bolt receiving portion 14 and assembled to the cap 11 to form a lock bolt.
[0014]
FIG. 5 is an explanatory diagram of a construction method of the lock bolt according to the second embodiment, in which 11 is a cap, 21 is a bolt steel material, 51 is a natural ground, 52 is a bore hole, and 53 is a fixing material.
First, a bore hole 52 having a predetermined depth is drilled in the natural ground 51. Next, a fixing material such as mortar, cement milk, or resin is injected or loaded into the bore hole 52. Thereafter, a lock bolt having the cap 11 attached to the bolt steel material 21 is inserted and driven into the bore hole. As the bolt is inserted, the fixing material 53 enters and fills the space SP from the fixing material introduction holes 15a to 15d provided at the tip of the cap, and the bolt steel material 21 and the cap 11 are firmly fixed and integrated. The inside gap is filled with the fixing material 53, and a fixing material filling state without a gap is obtained. As described above, the same effects as those of the first embodiment can be obtained.
[0015]
In addition to the above effects, according to the cap 11 of the second embodiment, the protruding portion 31 at the rear end of the cap is caught on the hole wall of the bore hole 52 even if the lock bolt is driven upward as shown in FIG. Therefore, the lock bolt can be prevented from falling. That is, conventionally, in the upward construction of the lock bolt, the fall prevention metal fitting is separately attached to the lock bolt. However, since the cap of the second embodiment has the fall prevention function, there is an effect that the fall prevention metal fitting can be made unnecessary.
In addition to the shape shown in FIG. 4, the overhanging portion 31 may have some expanded wing shape provided at the rear end portion of the cap main body portion 12.
In the second embodiment of FIG. 4, no step is formed in the cap main body portion 12, but it is also possible to form a step so that a bolt steel material having a plurality of diameters can be received.
The present invention has been described with reference to the embodiments. However, the present invention can be variously modified in accordance with the gist of the present invention described in the claims, and the present invention does not exclude these.
[0016]
【The invention's effect】
As described above, according to the present invention, the cap body for the lock bolt is configured by providing the hollow bolt receiving portion inside the cap body having the pointed portion and providing the fixing material introduction hole penetrating from the surface of the pointed portion to the bolt receiving portion. Therefore, it is possible to use the steel material as a lock bolt simply by attaching a bolt steel material cut to a predetermined length to the cap, and it is possible to omit the tip oblique machining and the tip blade machining at the factory.
In addition, according to the lock bolt cap of the present invention, it is possible to prepare a lock bolt by cutting a steel material on site in accordance with the required bolt length and attaching the cap to this. It is possible to easily respond to change requests etc. on site.
[0017]
Further, according to the present invention, since one or more steps are formed in the bolt receiving portion, the cap and bolt steel material are inserted by inserting the bolt steel material into the stepped portion of the bolt receiving portion corresponding to the diameter of the bolt steel material. Therefore, one cap can be used for a plurality of bolt steel materials having different diameters.
Further, according to the present invention, since the projecting portion is provided at the rear end portion of the cap body, the projecting portion is hooked on the borehole hole wall even if the lock bolt is driven upward, and the lock bolt Can be prevented, and the conventionally required fall-preventing bracket can be eliminated.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a lock bolt cap according to a first embodiment;
FIG. 2 is an explanatory diagram of an example of using a cap.
FIG. 3 is an explanatory diagram of a construction method of a lock bolt according to the first embodiment of the present invention.
FIG. 4 is a configuration diagram of a lock bolt cap according to a second embodiment.
FIG. 5 is an explanatory diagram of a construction method of a lock bolt according to a second embodiment of the present invention.
FIG. 6 is an explanatory view of a conventional lock bolt of the tip oblique cutting type.
FIG. 7 is an explanatory view of a conventional lock bolt of a tip sword tip machining type.
FIG. 8 is a diagram for explaining a conventional method of applying a pre-injection type full-surface adhesive lock bolt.
[Explanation of symbols]
11 .. Cap 12.. Cap body 13.. Point 14. Bolt receiving portion 14 a... First bolt receiving portion 14 b... Second bolt receiving portions 15 a, 15 b, 15 c and 15 d.

Claims (2)

In the cap of the lock bolt that is inserted into the bore hole filled with the fixing material and supports the natural ground,
A hollow bolt receiving portion is provided inside the cap body having a pointed end portion, and a step is formed in the bolt receiving portion to receive a lock bolt having a different diameter , and first and second receiving portions are provided. Furthermore, a cap for a lock bolt, comprising a fixing material introduction hole penetrating from the tip end surface to the bolt receiving portion. 2. The cap for a lock bolt according to claim 1, wherein a frustoconical overhanging portion is provided at a rear end portion of the cap main body.

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