JPH0412160Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an improvement of the lock bolt in the sprayed lock bolt method, so-called NATM method, in tunnel construction.

[Conventional technology and its problems]

As is well known, the sprayed rock bolt construction method involves embedding rock bolts radially into the ground in order to prevent the collapse of the ground in mountain tunnels. If it is injected, there is no need for a separate hole-drilling machine or grout injection pipe, and collapse of the hole wall will not be a problem even in a sandy ground.
Until now, such a special construction method has not been established, but if it were to be realized, the hollow lock bolt would be long, with a length of 2 to 3 meters or more.

On the other hand, in the case of earthy ground, the self-supporting time of the ground is extremely short, so it is not possible to cut and widen the required cross section all at once, and construction work is forced to be divided into smaller sections.

When driving lock bolts as supports in a tunnel divided into small sections like this,
Due to limited work space, it is difficult to insert long bolts.

The purpose of this invention is to take these circumstances into consideration and to realize a simple construction method using hollow lock bolts.
To provide a lock bolt for a sprayed lock bolt construction method, which can be installed in a predetermined length even in the case of a tunnel with a divided small cross section in earthy ground.

[Means for solving problems]

In order to achieve the above object, the present invention has an expandable and contractible multiple structure of an inner tube and an outer tube, and has a connecting and fixing means provided at each end of each tube, and a connecting portion for a hose is formed at the root of the inner tube. The main points are as follows.

[Effect]

According to the present invention, it can be expanded and contracted as needed, so if you start drilling and inserting with air in a short state at first, insert it into the ground, and then stretch it, it can be used in narrow spaces divided into small sections. However, long bolts can be installed.

[Embodiments] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Fig. 1 is a longitudinal sectional side view showing a first embodiment of the lock bolt of the present invention, and Fig. 2 is a longitudinal sectional side view of the main parts of the same. It has a tubular structure.

Fixing means for mutual attachment and detachment is formed at the ends of each tube 2 and 3, and in this embodiment, threaded portions 2a and 3a are provided as this fixing means.
Furthermore, a hose joint 5 is formed at the base of the inner tube 2.

3 and 4 show a second embodiment of the present invention,
A protrusion 2b is provided protruding from the inner tube 2 as a means for fixing the inner tube 2 and outer tube 3 to each other, and the protrusion 2b is provided from the outer tube 3.
An engaging groove 3b is formed in which the two engage with each other. Further, as a third embodiment, as shown in FIGS. 5 and 6, a pin 4 may be passed through and fixed, and various other fixing means can be considered.

In the above embodiments, only the case of a double tube structure consisting of the inner tube 2 and the outer tube 3 was shown, but a triple or quadruple structure may be used to increase the expansion/contraction ratio.

Next, to explain how to use it, as shown in Fig. 7, the lock bolt 1 is made short by overlapping the inner tube 2 and the outer tube 3, and the air hose 6 is connected to the end of the inner tube 2 to supply air from the tip. Drill holes while spraying.

When the inner tube 2 is inserted to a predetermined depth, the inner tube 2 is pulled out leaving only the outer tube 3 as shown in FIG. Complete the second stage of drilling.

Once the hole has been drilled in this way, replace the air hose 6 with a grout injection hose 7 as shown in Figure 10, and inject grout 8, which will be discharged from the tip and fill the gaps in and around the bolt 1. Filled.

Finally, remove the injection hose 7 and lock bolt 1.
The grout 8 can be left as is, but since the grout 8 is integrated inside and outside the lock bolt 1, the lock bolt 1 is also securely fixed.

[Effect of idea]

As mentioned above, the lock bolt for the sprayed lock bolt construction method of the present invention is a hollow type lock bolt that is used as an air discharge pipe for drilling and a grout injection pipe to simplify the process and can be used even on sandy ground. Can be constructed reliably. Furthermore, since the lock bolt itself can be expanded and contracted, it is possible to install a lock bolt of a predetermined length even in a narrow space with a small divided section.

[Brief explanation of the drawing]

FIG. 1 is a vertical side view showing a first embodiment of the lock bolt of the present invention, FIG. 2 is a vertical side view of the main parts of the same, FIG. 3 is a vertical side view showing the second embodiment, and FIG.
The figure is a vertical side view of the main part of the above, Figure 5 is a vertical side view of the third embodiment, Figure 6 is a vertical side view of the main part of the same, and Figures 7 to 10 are process explanations showing usage conditions. It is a diagram. 1...Lock bolt, 2...Inner tube, 3...Outer tube, 2a, 3a...Threaded part, 2b...Protrusion, 3b
... Engagement groove, 4 ... Pin, 5 ... Hose joint, 6 ... Air hose, 7 ... Grout injection part, 8 ... Grout material.

Claims (1)

[Scope of utility model registration request] For use in the sprayed lock bolt construction method, which has a multi-pipe structure with expandable and contractible inner and outer pipes, with connecting and fixing means provided at the ends of each pipe, and a hose joint formed at the root of the inner pipe. Rock Bolt.