JPH0571760B2 - - Google Patents

Description

[Detailed Description of the Invention] <<Industrial Application Field>> The present invention relates to a self-drilling bolt used in NATM, cutting, and embankment reinforcement methods.

《Prior art and problems》 In reinforced earth construction methods such as NATM and earth nailing methods, relatively short steel or FRP bolts are buried in earth and sand or bedrock, and the area around them is hardened with grout etc. to strengthen the reinforcement part. construction and stabilize tunnel walls and slopes.

In this type of construction method, in dense ground such as bedrock, a hole is first drilled with a rock drill, a fixing material such as cement milk or mortar is injected into the hole, and then a bolt is inserted and the fixing material is Fully adhesive fixation with bolts is performed.

On the other hand, in alluvial ground such as clay or sand, or collapsible ground such as talus or strongly weathered rock, the visibility of the hole wall cannot be maintained after drilling, and it is difficult to inject anchoring materials such as grout and bolts. It becomes impossible to insert the
Alternatively, even if these operations are performed, sufficient fixation is often not achieved.

For this reason, conventionally, when burying bolts in collapsible ground, a casing was used to prevent the hole wall from collapsing while drilling, or a self-drilling bolt with a hole expansion bit at the tip was used. However, both had the following problems.

That is, in the former method, it takes time to drill a hole using a casing, and the series of operations such as grout injection, bolt insertion, and casing removal after drilling become complicated, increasing both the construction period and the construction cost.

On the other hand, in the latter method, the bit at the tip is expensive and the bit is buried, which increases construction costs, and even if the hole is expanded with the bit at the tip, there is a risk that the ground will collapse by the time the fixing material is injected. Ta.

In order to solve this problem, it is conceivable to prepare a bolt with a shaft hole for injecting the fixing material and embed the bolt by impact or vibration, but this method does not require mechanical force. The disadvantage was that the mechanical strength was poor, with the bolts often bending or breaking when subjected to stress.

The present invention was made in view of the above problems, and its purpose is to provide a self-drilling bolt with excellent mechanical strength that is not damaged by vibrations, impacts, etc. There is a particular thing.

<Means for Solving the Problems> In order to achieve the above object, the present invention includes a solid jet bolt to which impact and/or vibration is applied from the rear end, and a solid jet bolt that is coaxial with the jet bolt and that is attached to the ground together with the jet bolt. a hollow cylindrical body embedded therein, defining an annular space between it and the jet bolt, and having a through hole formed therein for spouting the fixing material to the outside from the annular space; A jet is detachably connected to the jet bolt and the hollow cylindrical body to define a chamber chamber communicating with the annular space, and has a fixing material press-in port for press-fitting the fixing material into the chamber chamber. It is characterized by being equipped with an etchamber.

<<Embodiments and Operations>> Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIGS. 1 and 2 show an embodiment of a self-drilling bolt according to the present invention.

The bolt shown in the figure is generally composed of a solid jet bolt 10, a hollow cylindrical body 12 and a jet chamber 14, which are arranged coaxially with the jet bolt 10.

On the rear end side of the jet bolt 10, a force application part 10a to which impact and/or vibration is applied, and a male screw part 10b are continuously formed, and the tip part 10c is formed in a tapered shape.

A narrow ring 16 is fitted to a portion of the jet bolt 10 close to the tip 10c, and one end of the hollow cylinder 12 is fitted so as to be in contact with the outer peripheral surface of the ring 16. Cylindrical body 12
An annular space 1 is formed between the jet bolt 10 and the outer periphery of the jet bolt 10.
8 is defined. The outer periphery of the jet bolt 10 and the leading edge of the ring 16, and the outer periphery of the leading end of the ring 16 and the leading edge of the hollow cylindrical body 12 are fixed by welding.

At the other end of the hollow cylindrical body 12, an annular collar ring 20 is provided.
is fitted and fixed, and the jet chamber 14 is fitted in close proximity to the male threaded portion 10b of the jet bolt 10, with its distal end abutting the collar ring 20 and with the packing 22 interposed therebetween. The rear end edge of the hollow cylinder 12 and the inner periphery of the collar ring 20, and the outer periphery close to the rear end edge of the hollow cylinder 12 and the front end surface of the collar ring 20 are fixed by welding.

An O-ring 24 is interposed at the rear end between the outer peripheral surface of the jet bolt 10 and the inner peripheral surface of the jet chamber 14, and a chamber chamber 26 communicating with the annular space 18 is defined. .

The jet chamber 14 is fixed to the male threaded portion 10b of the jet bolt 10 by screwing a nut 30 with a spacer ring 28 interposed at its rear end.

On the other hand, as shown in FIG. 2, the annular space 18 is connected to the outside through a through hole 32 formed in the radial direction of the hollow cylindrical body 12 only in the vicinity of the tip 10c of the jet bolt 10. 3 formed through the ring 16 in the axial direction.
It is communicated with the outside through the nozzle through holes 33, 33. Further, on the side of the jet chamber 14, a press inlet 34 for a fixing material such as grout is provided so as to communicate with the chamber chamber 26, and is connected to a fixing material press-fitting hose (not shown). .

The self-drilling bolt constructed as described above is driven into the ground by fitting the applying portion 10a of the jet bolt 10 into a vibrator or the like and applying impact and/or vibration. Then, when the through hole 32 of the jet bolt 10 including the hollow cylindrical body 12 is buried in the ground, the fixing material is press-fitted through the injection port 34.

The press-fitted fixing material passes through the chamber chamber 26 and the annular space 18 and is then discharged from the through hole 32 and the nozzle through hole 33 toward the external ground.

Thereafter, the fixing material is press-fitted and the self-drilling bolt is mechanically applied at the same time.

The fixing material injected under high pressure sufficiently spreads through the through hole 32 to the outer periphery of the hollow cylinder 12 and into cracks in the ground caused by vibrations and impacts. Also, the tip 10 of the jet bolt 10 is inserted through the nozzle through hole 33.
The ejection energy of the fixing material released to the c side is directed to the ground on the tip end 10c side, and at the same time, an impact is applied from the rear end of the jet bolt 10, so the self-drilling bolt is It is quickly pressed into the ground.

When the anchor (jet bolt 10, hollow cylinder 12) is penetrated to a predetermined depth, for example, the depth at which the jet chamber 14 protrudes above the ground,
After the fixing material has solidified to a certain extent, the nut 30 and spacer ring 28 are removed, and the jet chamber 14 is removed, completing the embedding of one anchor.

Removed nut 30, spacer ring 28,
The jet chamber 14 is used again by being attached to another jet bolt 10.

FIG. 3 shows another embodiment of the self-drilling bolt according to the present invention, and only its features will be described below.

In this embodiment, the collar ring 20 is not fixed to the hollow cylindrical body 12, but threaded portions 34 are formed on the rear end of the hollow cylindrical body 12 and on the inner peripheral surface of the jet chamber 14, and these are screwed together. are combined.

In this configuration as well, it is buried in the same manner as in the above embodiment, and the same effects can be obtained.

<<Effects of the Invention>> As explained in detail in the embodiments above, according to the self-drilling bolt of the present invention, impact and/or vibration is applied to the jet bolt, which is the main body of the anchor, because it is solid. Not only is the rigidity high, but also the rigidity of the hollow cylinder defining an annular space between it and the jet bolt for ejecting the fixing material makes it possible to significantly increase mechanical strength compared to conventional hollow cylinders.

As a result of being able to increase mechanical strength in this way, it is possible to increase the impact force applied from the rear end of the jet bolt, and in this case, in this case, the jet bolt can be quickly buried in conjunction with the jetting energy of the fixing material, increasing construction efficiency. be able to.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an embodiment of the bolt of the present invention, Fig. 2 is a plan view of the same bolt as seen from the tip side,
FIG. 3 is a sectional view of a main part showing another embodiment. 10...Jet bolt, 12...Hollow cylindrical body,
14...Jet chamber, 16...Ring,
18... Annular space, 20... Tsuba ring, 24...
O-ring, 26...Chamber chamber, 28...Spacer ring, 30 Nut, 32...Through hole, 34...
...pressure inlet.

Claims (1)

[Scope of Claims] 1. A solid jet bolt to which impact and/or vibration is applied from the rear end, and an annular jet bolt that is coaxial with the jet bolt and buried in the ground together with the jet bolt, and that has an annular shape between the jet bolt and the jet bolt. A hollow cylindrical body defining a space and having a through hole for ejecting the fixing material to the outside from the annular space; and a chamber chamber coaxial with the jet bolt and communicating with the annular space. A jet chamber detachably connected to a jet bolt and a hollow cylindrical body and formed with a fixing material press-in port for press-fitting a fixing material into the chamber chamber. Perforated bolt.