JPS6043520B2 - Upward lock bolt construction method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for securing the roof during upward excavation in a mine using seamless long rock bolts.

Conventionally, when using rock bolts for roof security in upward excavation, the bolts must be carried up in a perpendicular direction from a horizontal tunnel or mining face, so the length of the bolt that can be used depends on the diameter and height of these tunnels or mining faces. When using long lock bolts of about 10 to 15 Tn, it was necessary to connect short lock bolts one after another and insert them.

Since rock bolts are inserted at multiple locations on the excavated surface, the necessity of such connection work complicates and makes process control complicated and difficult, which is not desirable from the standpoint of accident prevention. In the present invention, in order to eliminate the above-mentioned defects, a flexible rock bolt cut to the required length is inserted into the drill hole, and grout is injected around it to fix it. It is.

The construction method of the present invention will be explained below with reference to the drawings.
FIG. 1 shows an example of the construction method according to the present invention, in which a rock bolt 1 is made by cutting a flexible material such as wire to a predetermined length, and an anchor member, that is, a hanging body 2.
It is fixed by means such as welding or crimping.

The hanging body 2 includes a truncated conical fitting 3 and a wedge 4 in FIG.
It is shown as a so-called wedge type in which the wedge is activated by pulling the bolt when the bottom of the drill hole is reached, but other known latching bodies such as expansion type or can be used in any type, such as a tip-adhesive type. Next, a grouting agent injection vibe 6 having a vibe guide 5 at its tip is introduced into the drill hole. The vibe guide 5 also functions as a packer, as will be described later, and has an outer diameter corresponding to the inner diameter of the drill hole, and has a shape such as the one shown in FIG. It has a curved part and is brought into contact with the inner wall of the drill hole. The grouting agent injection vibe 6 penetrates through the vibe guide 5 and protrudes above it. Furthermore, the vibe guide 5 is made such that a lock bolt can pass through it. Regarding the insertion of the lock bolt, as shown in FIG. 1, the lock bolt can be pulled into the grouting agent injection vibe 6 and pulled out as the grouting agent injection operation, which will be described later, progresses. However, as shown in FIG. 2, for example, a lock bolt insertion hole is formed in the vibe guide 5 separately from the grouting agent injection vibe, and the lock bolt passes through the insertion hole when the injection vibe is introduced or withdrawn. It is also possible to do so.

When the tip of the grouting agent injection vibe 6 reaches the bottom of the drill hole, the grouting agent is supplied into the drill hole through the injection vibe 6 using a grout pump or compressed air (not shown).

At this time, the vibe guide 5 acts as a packer and prevents the extruded grout from leaking below the position of the vibe guide 5. As the injection of the grouting agent progresses, the injection vibrator 6 is guided by the packer 5 and is gradually pulled out while filling the drill hole in the upper section with the grouting agent and reaches the entrance of the drill hole. In this case, the drawing is carried out gradually and at a uniform speed so as not to create cavities in the drill hole. Thereby, the rock bolt 1 is fixed in the drill hole in a state surrounded by the grouting agent. When the grouting agent injection is completed and the vibe guide reaches the entrance of the drill hole, the injection hole is closed with a plug 7 made of rubber or the like as shown in FIG. 3, and the mortar is hardened. As mentioned above, wire can be used as the material for the rock bolt, but it is also possible to use a material that is flexible to the extent that it does not cause problems when being carried in from a horizontal mine shaft or mining face, and has a high tensile strength, such as a material that has a high tensile strength. Of course, FRP (fiber reinforced plastic) etc. can also be used.

However, in this case, measures such as providing a large number of small protrusions on the surface are taken to strengthen the bond with the mortar.
There are no particular limitations on the dimensions of the drill hole used to construct the construction method of the present invention and the tools used, but as a typical example, the depth of the drill hole is 10 to 15 TrL.
1 The inner diameter is about 46 to 50 mm, and the lock bolt is 16 mm in the case of wire. ．． In the case of FRP, a material of about 19 to 22 mm is used, and the inner diameter of the deaeration hole in FRP is 4 to 22 mm.
6Tf0n.

L According to the construction method of the present invention, it is possible to provide a desired long rock bolt support regardless of the specifications of the lower horizontal tunnel and the mining face, and it is possible to achieve great effects in terms of the mining process and security.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of the rock bolt supporting method of the present invention. FIG. 2 is an explanatory diagram showing a partially modified version of the method shown in FIG. FIG. 3 shows the configuration of the plug placed at the entrance of the drill hole. )l: lock bolt, 2: hanging body, 5: pipe guide and packer, 6: grouting agent injection vibe, 7: plug.

Claims (1)

[Claims] 1. A flexible grout rock bolt is inserted into the drilled drill hole, and the grout is poured into the drill hole while preventing the grout from escaping with a packer surrounding the tip of the grout injection pipe. In this method, the ceiling plate is supported by rock bolts for upward excavation work, in which the rock bolt is inserted, and then the lock bolt is drilled by operating the latch attached to the upper end of the rock bolt. The packer is fixed to the bottom of the hole, the lock bolt is inserted through the packer, the packer is raised to the bottom of the drill hole, and the injection pipe is pulled out while filling the drill hole with grout and using the packer as a guide. how to. 2. In the method according to claim 1, the grouting agent injection pipe reaches the bottom of the drill hole while housing the rock bolt therein, and the rock bolt is pulled out from the grouting agent injection pipe when grouting agent is injected. Method. 3. The method according to claim 1, wherein the lock bolt insertion hole is provided in the packer separately from the grouting agent injection pipe. 4. A method according to any one of claims 1 to 3, in which the lock bolt is a wire. 5. A method according to any one of claims 1 to 3, in which the rock bolt is made of FRP.