JPH0439360Y2 - - Google Patents

Description

[Detailed description of the invention] <<Industrial application>> This invention relates to lock bolts used for reinforcing the ground during excavation work such as tunnels, and is particularly suitable for fixing construction to support shell layers of shotcrete. Regarding lock bolts with metal fittings.

<Prior art and its problems> In civil engineering works such as tunnel construction, lock bolts with axial tensile strength are inserted and buried in the excavated surface along with hardening materials such as mortar to prevent the surrounding ground from collapsing or peeling. However, construction methods that improve the physical properties of the ground are being adopted.

As the lock bolts used in these construction methods, rigid bodies such as steel bars, deformed steel bars, and fiber-reinforced plastic rods are provided.

However, these rigid lock bolts have problems such as not being able to insert the specified length if the hole that has been drilled for a relatively long time is bent or displaced by a drifter, etc., and the bolt cannot follow the deformation of the hole. There was a need for a flexible locking bolt that could be inserted.

The applicant has proposed a structure that satisfies the above requirements.
We developed a new tensile reinforcing material that can also be used as a lock bolt.
This is proposed in Publication No. 18555). The tensile reinforcement material according to this application is made by twisting or braiding composite strands coated with a thermoplastic resin on the outer peripheral surface of a reinforcing fiber bundle impregnated with an uncured thermosetting resin, and then applying a thermosetting resin to the outer peripheral surface of the reinforcing fiber bundle. It is a rope-shaped material having a structure in which the thermoplastic resins of adjacent composite strands are cured and thermally welded together at the joints. By adopting such a shape, it has the flexibility to follow the displacement of the drilled part and the ability to resist the hardening material such as mortar that is filled into the drilled part before inserting the lock bolt. is realized.

By the way, when this type of lock bolt is driven into an excavation surface to support the ground, a fixing fitting is attached to the side head of the rock bolt.
In particular, the above-mentioned rope-shaped lock bolt had the following problems.

FIG. 4 shows an example of a conventionally used fixing fitting.

The fixing fitting 1 shown in the figure is of a so-called cone type, and includes a holding member 1a that is expanded at the rear end side, and
It consists of a cone 1b that is fitted into the expanded part,
The lock bolts were inserted into holes drilled in the axial direction of the cone 1b, and these were fixed with adhesive.

However, in this structure, the adhesion force between the lock bolt body and the cone 1b is obtained only by the adhesive, so the adhesion force is significantly smaller than the lock bolt's original tensile strength, and the lock bolt's performance is fully demonstrated. There was a problem that it was not done.

The present invention was developed in view of the above circumstances, and the purpose is to provide a new lock bolt equipped with a fixing fitting suitable for a rope-shaped lock bolt made of fiber-reinforced synthetic resin that has both flexibility and rigidity. shall be.

《Means for solving the problem》 To achieve the above purpose, the present invention is a system that is buried in the ground such as a tunnel, binds reinforcing fiber bundles with a thermosetting resin, and covers the outer periphery with a thermoplastic resin. The lock bolt body includes a lock bolt body made of strands, and a cylindrical fixing fitting that is fixed by filling an adhesive into one end of the lock bolt body. The fixing fitting has an inner diameter corresponding to the apparent diameter of the locking bolt, and includes an annular protrusion protruding from the inner surface and a threaded portion carved on the outer peripheral surface of the locking bolt. It has a cylindrical body that separates and stores the strands of the main body, and a central through hole in the cylindrical body through which the core strand among the plurality of strands is inserted, and strands other than the core strand are connected to the cylindrical body. It is characterized by consisting of a ring wedge that expands in between.

<<Operation>> According to the lock bolt having the above structure, the lock bolt main body is fixed by filling the adhesive with the strands separated and expanded between the cylinder body and the ring wedge, so that the lock bolt main body and the fixation are fixed. It is firmly connected to the metal fittings.

In addition, the cylindrical body has a threaded part carved into it, so
It can be easily installed on excavated ground by attaching a washer plate.

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

1 to 3 show an embodiment of a fiber-reinforced synthetic resin lock bolt according to the present invention.

The lock bolt shown in the figure is roughly composed of a lock bolt main body 10 and a cylindrical fixing fitting 12. As shown in FIG.

As shown in FIG. 3, the lock bolt main body 10 includes a core strand 10a made by binding reinforcing fiber bundles with a thermosetting resin and covering the outer periphery with a thermoplastic resin.
and each other strand 10a, 10b,...
It has a spiral rope-like structure in which the coverings of ... are fused and bonded to each other.

Specifically, the lock bolt body 10 is manufactured as follows.

First, uncured thermosetting resin materials such as unsaturated polyester resins and epoxy resins are made into high-strength reinforcing fibers with low elongation and strong retention properties such as glass fibers, aromatic polyamide fibers, polyester fibers, and vinylon fibers. Various polyethylenes, ethylene-vinyl acetate copolymers, various nylons, various ABS,
A thermoplastic resin such as various types of polypropylene is melt-extruded and coated in a ring shape, and then the coated portion is cooled to form an uncured composite strand. Note that the thermoplastic resin coating may be formed into a single layer or multiple layers using the above resin depending on the ease of fusion bonding of the coating portion after curing, which will be described later.

One of the above-mentioned uncured composite strands is used as the core strand 10a, and a plurality of uncured composite strands 10b, 10c, etc. are wound around the core strand 10a in a spiral shape at a predetermined pitch, and this is placed in a heating tank. The internal thermosetting resin is cured to obtain a spiral rope-shaped lock bolt body 10. In this case, it is desirable to weld and join the coating layers of adjacent composite strands by heat generation of the thermosetting resin and heating from the outer periphery in the heating tank, so the composition of the thermosetting resin Consideration should be given to the selection of catalysts, catalysts, etc., and the setting of conditions such as heat curing temperature.

The spiral rope-shaped lock bolt body 10 thus hardened is cut to a required length,
A fixing metal fitting 12 is fixed to the driving side head.

The fixing fitting 12 includes a cylindrical body 14 with both ends open, and a ring wedge 16 installed inside the cylinder 14.

An annular protrusion 14a having an inner circumferential diameter slightly larger than the apparent diameter of the lock bolt main body 10 is provided on the inner circumference of the cylinder 14 on the ground side, and an annular protrusion 14a is provided on the outer circumferential surface thereof over the entire length. A threaded portion 14b is carved.

The ring wedge 16 has a central through hole 16a in its center through which the core strand 10a is inserted, and a wedge surface inclined toward the center at one end. In order to fix the fixing fitting 12 to the lock bolt body 10, first, the lock bolt body 1 is
The coating of each strand 10a, 10b... of 0 is peeled off according to the length of the cylinder 14, and each strand 10
Separate a, 10b...

Then, the separated part is attached to the annular protrusion 1 of the cylinder 14.
4a side, the core strand 10a of the lock bolt body 10 is inserted into the center through hole 16a of the ring wedge 16 from the opposite side of the cylinder 14, and the ring wedge 16 is moved to the longitudinal center of the cylinder 14. .

As a result, the strands 10b, 10c, . . . other than the separated core strand 10a are spread out as shown in FIG. .

In this state, attach the rear end of the cylinder 14 with a tape 18, for example.
etc., inject the adhesive 20 from the tip side, and harden the adhesive 20 to lock the lock bolt body 1.
0 and the fixing metal fitting 12 are fixed.

In this case, in order to facilitate injection of the adhesive 20, an injection hole may be provided at the longitudinal center of the cylindrical body 14.

The lock bolt main body constructed as described above is inserted from the lock bolt main body 10 side into a hole drilled in the ground 22 and filled with a fixing material such as grout, and the washer plate 24 is attached.
A nut 26 is screwed onto the threaded portion 14b of No. 4.

The present inventors actually manufactured a lock bolt having the above-mentioned configuration, and tested its effectiveness as follows.

<<Specific Example>> First, strand 10 of rope-shaped lock bolt
As a, 10b..., a glass roving was impregnated with uncured unsaturated polyester resin, and this was shaped to obtain an uncured rod with an outer diameter of 6.5 mm, which was inserted into a crosshead die. The strands were coated with high-density polyethylene to an outer diameter of 7.2 mm, immediately cooled to form a strand of primary coating, and then passed through the crosshead die again to reduce the vinyl acetate content.
OD by 15% ethylene vinyl acetate copolymer
A composite strand of 7.7 mm was obtained.

This is fed to a twisting machine to make one core strand 1.
Six strands 10b, 10c are placed around the outer circumference of 0a.
... are arranged in a spiral shape to obtain a 1 x 7 type rope with a twist pitch of 225 mm, which is passed through a heating tank to harden the unsaturated polyester resin inside the strand at 98°C, and each strand 10a ,10
The ethylene-vinyl acetate copolymer coatings on the outer periphery of b... are fused and bonded to each other, and the outer strands 10b, 10c... have an apparent outer diameter of approximately 23 mm, a unit weight of 510 g/m, and a tensile strength. is 18
A rope-shaped lock bolt body 10 of 100 lbs. was obtained. The cross-sectional shape of this lock bolt body 10 is as shown in FIG.

This lock bolt body 10 was cut into a length of 4 m, and one end of the lock bolt body 10 was coated with thermoplastic resin to a length of 150 m.
Peel off about mm, each strand 10a, 10b
... was made possible to be displaced.

Next, an annular projection 14a with an inner diameter of 23 mm and a thickness of 10 mm.
and a cylinder 14 with a length of 150mm, which has an inner cylinder part with an inner diameter of 26mm and an M36 thread with a pitch of 4mm on the entire length,
After inserting into the part where the coating was peeled off, the inner diameter is 9.
mm, the outer diameter is 12mm, the total length is 10mm, and 3~
For the 5 mm portion, a tapered ring-shaped wedge 16 is attached to each strand 10b, 1 on the outer periphery.
While expanding 0c..., core strand 10
A and placed at a position 75 mm from the end where the coating was peeled off, and the lower end of the rear cylinder 14 was sealed with butyl tape to form a seat.

Next, epoxy adhesive 20 (manufactured by Konishi Co., Ltd.) was applied.
CL-60) 100 parts, hardening agent 15 parts, calcium carbonate 20 parts
This is injected from the annular protrusion 14a side of the cylindrical body 14 to fill the inside of the cylindrical body 14 with the adhesive filling resin, and after curing at room temperature, it is further heated at 80°C. After hardening, a rope-shaped lock bolt with the fixing metal fitting 12 fixed thereon as shown in FIG. 1 was obtained.

This lock bolt is inserted into a simulated rock bed made of a steel pipe with an inner diameter of 50 mm filled with mortar, and a flat washer of 150 x 150 mm and a thickness of 12 mm is clamped on the fixing fitting 12 side by an M36 nut to reduce the pulling force from the steel pipe side. Measurements were made on five samples. As a result, the pulling force is 16~
18 tons or strong enough to break the threaded part 14b, and the almost rope-shaped lock bolt body 1
It was possible to develop a fixing force comparable to that of 0.

[Comparative Example 1] The same lock bolt body 1 as in the above embodiment was used, the annular protrusion 14a and ring wedge 16 were removed from the fixing fitting of the present invention, and a cylindrical body with open ends was used. This was fixed with the same adhesive as in the above example.

The lock bolt with this configuration has a pulling strength of 5 to 5.
Only 7 tons were obtained, and the state of the breakage was found to be cohesive failure of the adhesive filled between the outer periphery of the lock bolt body 10 and the inner periphery of the fixing fitting.

[Comparative Example 2] The fixing tool 1 having a cone-shaped cross section as shown in FIG.
0, and the drawing strength was measured in the same manner as described above. As a result, the drawing strength was 6 to 12 tons, and there was considerable variation in the values.

As is clear from the above test results, the anchoring force of the rope-shaped lock bolt of the present invention is determined by the anchor locking force due to the unevenness of the outer periphery strands 10b, 10c, etc. of the lock bolt body 10 buried in the hole, and This can be achieved by interposing a seat plate between the fixing metal fitting 12 fixed to the section and the shotcrete layer of the ground.

Therefore, the size, pitch, etc. of the screws machined on the outer periphery of the fixing metal fitting 12 must be set so that the screw strength corresponds to the sum of the tensile strength of each outer periphery strand 10b, 10c, . . . of the rope-shaped lock bolt body 10. No.

In addition, by expanding each of the outer circumferential strands 10b, 10c, . The total sum of these dispersion forces is shared by the adhesive force with the inner cylindrical portion of the cylindrical body 14 and the locking force of the annular protrusion 14a, thereby preventing the formation of a layer where stress is concentrated and causes cohesive failure of the adhesive. It is believed that, in combination with the selective use of the adhesive 20 having high adhesive strength, it becomes possible to effectively exhibit the tensile strength inherent in the lock bolt.

<<Effects>> As explained in detail above, the lock bolt of the present invention is fixed with a fixing metal fitting that can develop a fixing force commensurate with the tensile strength of the lock bolt body, which is the base material, and the lock bolt body has a special rope-like shape. Due to the structure, the insertion can follow the displacement of the drilled part, and it can be inserted against the hardening material such as mortar filled in the drilled part, so it is possible to use relatively long lock bolts. In addition to making it possible to extend the excavation length per cycle in tunnel excavation work, it is also possible to use a washer between the pouring head and the ground (shotcrete layer) in fixed construction to support a shotcrete layer, etc. By tightening the plate toward the ground, it is possible to develop a fixing force corresponding to the tensile strength of the lock bolt.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a main part showing an embodiment of the lock bolt according to the present invention, Fig. 2 is a - sectional view of Fig. 1, Fig. 3 is a cross-sectional view of the lock bolt main body, and Fig. 4 is a conventional fixing metal fitting. FIG. 10... Lock bolt body, 10a... Strand, 12... Fixing metal fitting, 14... Cylindrical body, 14a
... Annular projection, 14b ... Threaded part, 16 ... Ring wedge, 18 ... Tape, 20 ... Adhesive, 22 ...
...Ground, 24...Washer plate, 26...Natsuto.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A lock bolt body that is buried in the ground such as a tunnel and is made of a strand of reinforcing fiber bundles bound with a thermosetting resin and whose outer periphery is covered with a thermoplastic resin; A cylindrical fixing fitting is filled with adhesive and fixed to one end of the lock bolt body, and the lock bolt body has a spiral rope-like structure in which a plurality of strands are fused and bonded to each other, The fixing fitting has an inner diameter corresponding to the apparent diameter of the locking bolt, and has an annular protrusion projecting on the inner surface and a threaded portion carved on the outer circumferential surface, and is configured to separate the strands of the locking bolt body. A ring having a cylindrical body to be housed, and a central through hole in the cylindrical body through which a core strand among the plurality of strands is inserted, and through which strands other than the core strand are spread between the cylindrical body and the cylindrical body. A fiber-reinforced synthetic resin lock bolt characterized by consisting of a wedge. (2) The cylindrical body has an inner periphery larger in diameter than the inner diameter of the annular projection plus at least twice the wall thickness of the ring wedge, and a length of at least 1/2 of the twist pitch of the lock bolt body. A lock bolt made of fiber-reinforced synthetic resin according to claim 1 of the registered utility model, characterized in that it has a