JPH0672520B2 - Self drilling bolts - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION << Industrial Application Field >> The present invention relates to a self-drilling bolt used for a reinforcement method for NATM, cut soil, and embankment.

<Conventional technology> Reinforced earth methods such as NATM and earth nailing methods are used for relatively short steel or FRP on soil or rock.
A bolt made of steel is buried, and the surrounding area is hardened with grout or the like to construct a reinforcing part, which stabilizes the tunnel wall surface and slope.

In this type of construction method, in the case of solid ground such as rock, pre-drilling with a rock drill, etc., injecting fixing material such as cement milk or mortar into the hole, then inserting bolts The entire surface of the bolt is fixed by adhesion.

On the other hand, in alluvial ground such as clay or sand, or collapsible ground such as talus or weathered rock, the hole wall cannot maintain its self-sustainability after drilling, and pouring of fixing material such as grout and insertion of bolts In many cases, it becomes impossible, or even if these operations are performed, sufficient fixation cannot be obtained.

Therefore, conventionally, (1) when embedding a bolt in a collapsible ground, a casing is used to prevent the wall of the hole from collapsing, or (2) a tip is provided with a bit for expanding the hole. It is practiced to use self-drilling bolts.

<< Problems to be Solved by the Invention >> By the way, all of them have the following problems.

That is, in the above (1), it takes time to drill a hole using a casing, and a series of operations such as grout injection, bolt insertion, and casing withdrawal after drilling become complicated, which increases both the construction period and the construction cost.

On the other hand, in the above (2), since the tip bit is expensive and this is buried, the construction cost is high, and even if the tip bit is expanded, the ground may collapse before the fixing material is injected. there were.

On the other hand, for example, as described in JP-A-57-36215, the work is simplified and the construction period is shortened by pouring the fixing material into the periphery of the drilled hole while perforating the ground. There is.

That is, the invention described in this publication is a hollow pipe anchor 1 that is rotatably inserted into the ground and injects the hardening material 10 from the nozzle hole 4 formed at the tip, and is removable from the rear end of this pipe anchor. The rotary shaft 7 is connected to the rotary shaft 7 in which the communication passage 12 communicating with the pipe anchor is formed, and the rotary device 6 rotatably supporting the rotary shaft. It is effective in inserting it into the ground to a depth and injecting the hardening material from the nozzle hole of the pipe anchor and then removing the pipe anchor from the rotating shaft and leaving it in the ground.

In the device used for such a conventional drilling method, it is necessary to remove the pipe anchor from the rotary shaft in order to leave the pipe anchor in the ground. Is appropriate. However, if the pipe anchor and the rotary shaft are screwed together, the hardened material always penetrates into the threaded joints of the two, and the hardened material solidifies, and the pipe anchor and the rotary shaft may become inseparable. There is. Moreover, when a pressing force is applied from the rear end of the pipe anchor, the pressing force directly acts on the screw, the liquid tightness of the screw is deteriorated, and the hardened material easily penetrates into the screw.

The present invention has been made in view of the above problems, while pouring a fixing material is injected into the periphery of the drilling hole, thereby simplifying the work and shortening the construction period, It is possible to maintain liquid tightness between the bolt body and the ground press-fitting rod, which are screwed to each other so as to be detachable, and prevent the rod press-fitted from the bolt body into the ground to be inseparable. The purpose is to provide a self-drilling bolt.

<< Means for Solving the Problems >> In order to achieve the above object, the present invention provides a bolt body to which any one of a striking force, a pressing force, a rotating force, and a vibration or a combination thereof is applied from a rear end portion, A jet bolt consisting of a swivel sub screwed into the tip hole of the bolt body, a ground press-fitting rod screwed into the tip hole of the swivel sub and having a jet injection port at the tip, and a bolt of this jet bolt The swivel into which the fixing material is press-fitted is supported while supporting the main body so that the fixing material is press-fitted. The bolt body and the swivel sub, the rear end side of the screw joint, and the swivel sub and the ground press-fitting rod screw joint. A seal member is provided on the rear end side of the swivel sub to provide a liquid-tight seal between the two, and in each coupled state, the rear end of the ground press-fit rod contacts the hole front end of the swivel sub, and the rear end of the swivel sub Is in contact with the front end of the hole of the bolt body.

<< Embodiment >> An embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a sectional view showing the overall structure of a self-drilling bolt according to a first embodiment of the present invention, and FIG. 2 (a) is an enlarged view of part A of FIG.

In the figure, this self-drilling bolt is a jet bolt 1
And a swivel 3 connected to the rear of the jet bolt 1.

The jet bolt 1 includes a thick ground press-fitting rod 1a having a cone-shaped tip, a swivel sub 2 having a hole at its tip for detachably connecting the rear end of the rod 1a, and a swivel sub 2. The rear end of the bolt main body 31 has a hole at its front end so as to be detachably screwed and is supported by the swivel 3 so as to be relatively rotatable.

A fixing material press-fitting hole 11 is formed in the central shaft portion of the ground press-fitting rod 1a.
Is formed, and a jet outlet 13 coaxial with the press-fitting hole 11 and a plurality of jet outlets 14 intersecting at a predetermined angle θ are formed respectively. The jet outlet 13 at the center is the press-fitting hole.
A chip (13a) made of hard metal is embedded in (11) and a hole is formed by punching the center part.

The swivel sub 2 has the fixing material press-fitting hole 11 at the center thereof.
A communication hole 21 communicating with the female screw portion 22 that is screwed into a male screw portion 12 formed on the outer periphery of the rear end of the ground press-fitting rod 1a at the inner peripheral portion of the front end thereof, and the outer peripheral portion of the rear end of the bolt. A male screw portion 23 that is screwed onto the tip of the main body 31 is formed. A seal ring 22a (sealing member) is arranged on the outer periphery of the tip of the swivel sub 2 on the rear end side (the left side in the figure) of the screw coupling portion between the rod 1a and the swivel sub 2, and the rod 1a and the swivel sub 2 are arranged. It is liquid-tightly sealed in a screwed state with. The rear end of the rod 1a is in contact with the front surface of the taper portion formed on the inner wall of the hole of the swivel sub 2.

A hole is formed at the tip of the bolt body 31 for detachably screwing the rear end of the swivel sub 2, and the hole is formed in the male screw portion 24 formed on the outer periphery of the rear end of the swivel sub 2. A mating female screw portion 31a is formed. A seal ring 31b (sealing member) is fitted to the rear end side of the screw coupling portion between the bolt body 31 and the swivel sub 2, and the swivel sub 2 and the bolt body 31 are liquid-tightly sealed in a screwed state. . The rear end portion of the swivel sub 2 is in contact with the front surface of the tapered portion formed on the inner wall of the hole of the bolt body 31. A fixing material press-fitting hole 31c is formed in the bolt body 31 so that one end communicates with the communication hole 21 and the other end is opened in the inner circumference of the ring portion 32.

Further, the swivel 3 includes a ring portion 32 and a thrust receiving plate which are rotatable relative to the outer periphery of the bolt body 31 and are liquid-tightly provided.
It consists of 33. On the other hand, a ring-shaped groove 32a communicating with the press-fitting hole 31c is formed in the inner peripheral portion of the ring portion 32, and the press-fitting hole 32 communicating with the ring-shaped groove 32 is formed.
b is opened to the outer circumference. A high pressure hose 35 is connected to the press-fitting hole 32b via a hose joint 34.
The high-pressure hose 35 communicates with a high-pressure grout pump for feeding a fixing material such as cement milk.

Further, a plurality of seal rings 36 are provided on the inner circumference of the ring portion.
And a grease hole 37 for supplying a lubricant is formed in each seal ring 36, and the outer periphery of the grease hole 37 is covered with a grease cup 38.

A cushion plate 39 also serving as a seal is provided between the front end portion of the thrust receiving plate 33 and the rear end of the ring portion 32 and the bolt body 31 for damping vibration and impact in the thrust direction.

The surface shape of the ground press-fitting rod 1a is modified to have a deformed shape 1b such as a mesh to increase the adhesive force with the fixing material, as shown in FIG. 2 (b).

The self-drilling bolt having the above configuration is connected to a device for performing a striking force, a pressing force, a rotating force, a vibration on the female screw portion 31d formed at the rear end of the bolt body 31, or a combination thereof. By applying force F in the direction of the arrow, the jet bolt 1 at the tip is driven into the ground, and a fixing material such as cement milk that is pressure-fed from a pressure-feeding pump (not shown) is punched into the ground while press-fitting holes 32b, 31c and communication holes 21. Then, it will be ejected from the jet ejection ports 13 and 14 along the press-fitting hole 11. At this time, the fixing material is not only the tip of the jet bolt 1 but also
Since the jet is ejected at an angle corresponding to the intersection angle θ of the jet outlets 14, the ground press-fitting rod 1a is soaked into the ground that the entire outer peripheral portion of the ground press-fitting rod 1a is largely covered. As a result, the fixing range of the jet bolt 1 with respect to the ground becomes large.

By the way, the fixing material does not permeate into the screw coupling portion by the seal rings 22a and 31b. Further, even if a pressing force or a striking force is applied from the rear end portion of the bolt body 31, the pushing force or the striking force is applied to the contact portion between the taper portion formed in the hole of the bolt body 31 and the swivel sub 2 or the swivel sub portion. As a result of being transmitted to the contact portion between the taper portion formed in the second hole and the rod, it does not directly act on the screw coupling portion, so that the liquid tightness of the screw coupling portion is maintained well.

If the drilling length is long, drilling can be performed while connecting the intermediate rod 15 to the coupling 16 one after another at the rear end of the ground press-fitting rod 1a as shown in FIG.

And if the ground press-fitting rod 1a is completely driven in,
The swivel sub 2 may be removed from the ground press-fitting rod 1a and the ground press-fitting rod 1a may be buried as it is, or both the ground press-fitting rod 1a may be pulled out and, instead, a reinforcing bar or a reinforcing material may be buried.

Further, the crossing angle θ of the jet ejection port 13 with respect to the press-fitting hole 11 may be 30 ° to 40 °, or more or less, which is the angle at which the fixing material easily penetrates into the ground drilled. You can set it to.

Next, FIG. 4 shows a second embodiment of the ground press-fitting rod 1a.

The ground press-fitting rod 1a has a female screw portion 101 formed at the rear end portion of the thin hollow pipe 100 and is connected to the swivel sub 2 via a coupling 4. A tip 102 made of hard metal is fixed to the tip of the bolt by welding 103. The tip portion 102a of the tip 102 is formed in a cone shape as described above, and a large-diameter hole is formed in its hollow.
102b is formed, and further jet bolt ejection ports 102c and 102d communicating with the large diameter hole 102b are formed at the tip end of the jet bolt.

In this embodiment, the relatively inexpensive thin-walled pipe 100 can be used, so that it can be constructed at low cost.

Next, FIG. 5 shows a modification of the second embodiment, in which a plurality of ring-shaped anchor portions 105 are provided on the outer periphery of the thin pipe 100.
Is fixed by welding or the like.

In this modified example, since the anchor portion 105 has a resistance in the pull-out direction, when it is buried, a strong holding strength is obtained.

<< Effects of the Invention >> As described in detail in each of the embodiments above, according to the self-drilling bolt according to the present invention, the fixing material can be permeated into the ground around the jet bolt while boring the ground. The work of fixing the ground that easily collapses can be shortened, and the effect of improving the ground around the bolt is high, and the construction period and cost can be greatly reduced.

Further, when the ground press-fitting rod is left in the ground, the rod and the swivel sub are screwed together, and the swivel sub and the bolt body are screwed together, so that the rod can be easily removed. Since both sealing members are provided on the rear end side of the connecting portion, it is possible to prevent the fixing material from penetrating into the screw connecting portion, and further, the rear end portion of the rod contacts the front end portion of the hole of the swivel sub, and , The rear end of the swivel sub is in contact with the front end of the hole in the bolt body, and even if a striking force is applied from the rear end of the bolt body, the striking force does not directly act on the threaded part, so the liquid tightness of the threaded part Does not deteriorate, and as a result, the rod is not incapable of being removed.

[Brief description of drawings]

1, 2 (a), (b), and 3 show a first embodiment of the present invention. FIG. 1 is a general view, and FIG. 2 (a) is a first view.
FIG. 4B is an enlarged view of part A of the figure, FIG. 4B is a partially enlarged view of the outer circumference of the jet bolt, FIG. 3 is a sectional view showing a state in which an intermediate bolt is connected to the jet bolt, and FIG. FIG. 5 is a sectional view of a jet bolt according to the embodiment, and FIG. 5 is a sectional view showing a modification of the second embodiment. 1 ... Jet bolt, 1a ... Tip part 2 ... Swivel sub 3 ... Swivel, 11 ... Fixing material press-fitting hole 13,14, 102c, 102d ... Jet ejection port 31c, 32b ... Press-fitting hole

Claims (1)

[Claims] 1. A bolt main body to which any one of a striking force, a pressing force, a rotational force, and a vibration, or a combination thereof is applied from a rear end portion, a swivel sub screw-coupled into a hole at a front end portion of the bolt main body, A jet bolt consisting of a ground press-fitting rod with a jet injection port formed in the tip end that is screwed into the tip hole of the swivel sub, and the bolt body of the jet bolt is rotatably supported, and the fixing material is press-fitted. A swivel and a self-drilling bolt in which a fixing hole press-fitted into the swivel is formed in the jet bolt and the swivel to communicate with the jet injection port. Side, and a sealing member for liquid-tightly sealing the swivel sub and the ground press-fitting rod to the rear end side from the screw coupling portion. In addition, the rear end of the ground press-fitting rod contacts the front end of the hole of the swivel sub, and the rear end of the swivel sub contacts the front end of the hole of the bolt body in each coupled state. Self-drilling bolt.