JPH10184297A - Lock bolt installation method - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a rock bolt construction method capable of completely filling a ground hole with a grout material and fixing the lock bolt to the ground hole with high fixing strength. SOLUTION: A ground hole 2 opening downward is formed on a wall surface 1 of an excavated lateral hole. The opening of the base hole 2 is closed with a seal material 3, and a lock bolt 4 and an injection nozzle 5 formed in a pipe shape are inserted into the base hole 2 through the seal material 3. Then, the grout material 6 is injected into the base hole 2 from the injection nozzle 5, the inside of the base hole 2 is filled with the grout material 6, and the grout material 6 is cured. Thereafter, the plate 7 is inserted into the end of the lock bolt 4 protruding from the base hole 2 so that the plate 7 abuts on the opening edge of the base hole 2 and the outer periphery of the end of the lock bolt 4 protruding from the base hole 2. The nut 7 is screwed into the male screw 8 provided in the above, and the plate 7 is pressed against the opening edge of the base hole 2. The grout material 6 can be injected without trapping air in the base hole 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing a rock bolt used to reinforce an excavated surface when constructing a tunnel or the like.

[0002]

2. Description of the Related Art As one of tunnel excavation methods, NA
TM method (New AustriaTunnel Me)
th) is conventionally provided. This NATM method is a method in which the excavated surface is reinforced by using a lock bolt provided with an external thread on the outer periphery of the end. Insert the lock bolt into each base hole by protruding the end provided, fill the base hole with grout material, fill it, harden the grout material, fix the lock bolt in the base hole, and fix the base hole of the lock bolt The plate is inserted into the end protruding from the hole, and a nut is screwed into the lock bolt so that the plate is pressed against the opening edge of the base hole. By pressing the plate against the opening edge of the foundation hole in this way, the lock bolt fixed to the foundation hole is tensioned, and the tension is exerted by the lock bolt fixed to the excavation surface to reinforce the excavation surface, and This is to prevent the collapse from occurring.

[0003] When the rock bolts are constructed as described above, the ground holes are drilled in the ceiling surface of the tunnel so that the openings face downward. Therefore, grout materials prepared by mixing cement, sand, and the like with water are ground. The work of injecting and filling the holes requires a certain measure. FIG. 5 shows an example of this. First, as shown in FIG. 5 (a), the opening of a base hole 2 drilled in the ceiling of the tunnel wall 1 is closed with a sealing material 12, and the lock bolt 4 is passed through the sealing material 12. Insert. The lock bolt 4 is formed of a pipe having both ends open. A male screw 8 is provided on the outer periphery of one end of the lock bolt 4. The lock bolt 4 has an end provided with the male screw 8 projected from the base hole 2 and inserted into the base hole 2. Next, a grout material 6 is fed by connecting a hose to the lower end of the lock bolt 4, and the grout material 6 is injected into the base hole 2 through the lock bolt 4 formed of a pipe as shown in FIG. Since the opening of the base hole 2 is sealed by the sealing material 12, the grout material 6 injected into the base hole 2 does not leak.
Then, as shown in FIG. 5 (c), the grout material 6 is filled in the ground hole 2, and then the grout material 6 is cured in the ground hole 2, so that the lock bolt 4 is fixed to the ground hole 2 with the hardened grout material 6. I do. Thereafter, as shown in FIG. 5D, the plate 7 provided with the through hole 17 is inserted into the lock bolt 4 through the through hole 17, and the male screw 8 of the lock bolt 4 is further inserted.
The plate 9 is pressed against the nut 9 so that the plate 7 is pressed against the opening edge of the base hole 2.

[0004]

As described above, the grout material 6 is injected into the base hole 2 through the pipe-shaped lock bolt 4 passed through the base material 2 through the sealing material 12 to thereby open the base hole 2 opening downward. 2 can be filled with the grout material 6, but the grout material 6 injected into the base hole 2 from the upper end of the lock bolt 4 is filled with the seal material 12 as shown in FIG. 2 is filled in the base hole 2 so that the liquid level rises sequentially, so that the air in the base hole 2 is confined in the base hole 2 above the liquid level of the grout material 6. become.

[0005] Therefore, as shown in FIG. 5 (c), a space S in which the grout material 6 is not filled is generated behind the base hole 2 by the air trapped in the base hole 2. In the space S where the grout material 6 is not filled, the lock bolt 4 is not fixed to the ground hole 2, so that the fixing strength of the lock bolt 4 to the ground hole 2 is weakened, and the reinforcing effect of the rock bolt 4 on the excavation surface is reduced. There was a problem that it was not possible to obtain a high price.

[0006] Further, since the inside of the base hole 2 is closed with the sealing material 12 and the inside cannot be seen, there is also a problem that it is impossible to confirm whether the ground hole 2 is filled with the grout material 6. Was. The present invention has been made in view of the above points, and provides a rock bolt construction method capable of completely filling a grout material in a ground hole and fixing the lock bolt to the ground hole with high fixing strength. It is another object of the present invention to provide a method of constructing a lock bolt that can confirm filling of a grout material into a base hole.

[0007]

According to the present invention, there is provided a method of constructing a lock bolt, comprising: drilling a base hole 2 opening downward on a wall surface 1 of an excavated lateral hole; closing the opening of the base hole 2 with a sealing material 3; A lock bolt 4 and an injection nozzle 5 formed in a pipe shape are inserted into the base hole 2 through the sealing material 3,
The grout material 6 is injected from the injection nozzle 5 into the ground hole 2, the ground hole 2 is filled with the grout material 6, and the grout material 6 is hardened. 7, the plate 7 is brought into contact with the opening edge of the base hole 2, and a nut 9 is screwed into a male screw 8 provided on the outer periphery of an end of the lock bolt 4 protruding from the base hole 2, thereby mounting the plate 7 on the base. It is characterized by being pressed against the opening edge of the hole 2.

According to the second aspect of the present invention, when the grout material 6 is injected into the base hole 2 from the injection nozzle 5, the grout material 6 is injected from the end of the lock bolt 4 protruding from the base hole 2.
When grout comes out, the grout material 6 is stopped from being injected.

[0009]

Embodiments of the present invention will be described below. An elongated and deep ground hole 2 is drilled in a ceiling surface or side wall surface 1 of a lateral hole formed by excavating the ground such as a tunnel or a tunnel using a drilling machine or the like. The base hole 2 is formed such that the opening is directed downward or obliquely downward.

On the other hand, in the present invention, the lock bolt 4 is
A lock made of a metal pipe as shown in (a) is used, and a male screw 8 is provided on the outer periphery of one end of the lock bolt 4. FIG. 3 shows an example of the sealing material 3 used in the present invention. The sealing material 3 is formed in a sealed bag shape as a whole, and is filled with air or a filling material such as a grout material to be described later through an injection port 13. It is designed to be inflatable. In FIG. 3B, 1
Reference numeral 4 denotes a stopper that is detachably fitted into the inlet 13. A lock bolt through hole 15 is provided at a substantially central portion of the seal material 3 so as to be opened vertically, and a nozzle through hole 16 is provided at a position near an end of the seal material 3 so as to be vertically opened. FIG. 3 shows the sealing material 3 in a state where the filler is filled and expanded.

When installing the lock bolt, first, the lock bolt 4 is passed through the lock bolt through hole 15 of the sealing material 3 not filled with the filler, and the injection nozzle 5 is passed through the nozzle through hole 16. And the sealing material 3 passed through the injection nozzle 5 is inserted into the opening of the base hole 2. Then, by injecting a filler into the sealing material 3 and expanding the sealing material, the sealing material 3 is brought into close contact with the inner periphery of the base hole 2 as shown in FIG. When the sealing material 3 is expanded in this manner, the diameters of the lock bolt through hole 15 and the nozzle through hole 16 become small, so that the lock bolt 4 and the injection nozzle 5 are located on the inner periphery of the lock bolt through hole 15 and the nozzle through hole 16. It will be adhered.

As described above, the lock bolt 4 and the injection nozzle 5 can be inserted into the base hole 2 through the seal material 3 as shown in FIG. 1A, and the opening at the lower end of the base hole 2 is sealed with the seal material. 3 and the lock bolt 4 can be mounted in the base hole 2. here,
The lock bolt 4 is inserted into the base hole 2 so that the end provided with the male screw 8 protrudes from the base hole 2, and it is preferable that the lock bolt 4 is inserted so that the upper end of the lock bolt 4 reaches as far as possible into the base hole 2.

At this time, a lock bolt fall prevention device 20 is attached to the upper end of the lock bolt 4 to prevent the lock bolt 4 from falling. As shown in FIG. 2B, the lock bolt fall prevention device 20 has a cylindrical tubular portion 2.
3 is formed by providing a plurality of leg pieces 21 of the same length radially projecting obliquely downward at the lower end of the cylindrical portion 23. The cylindrical portion 23 has a slit 2 extending along its axial direction.
2 is provided so that a radial elastic deformation force is generated in the cylindrical portion 23. The lock bolt fall prevention device 20 is attached by fitting the cylindrical portion 23 to the outer periphery of the upper end of the lock bolt 4. When the lock bolt 4 to which the lock bolt preventing tool 20 is attached is inserted into the base hole 2, the tip of each leg 21 provided on the lock bolt preventing tool 20 as shown in FIG. To prevent the lock bolt 4 from dropping from the ground hole 2. Further, the tip of each leg piece 21 provided on the lock bolt prevention tool 20 abuts on the inner periphery of the base hole 2 so that the lock bolt 4 can be positioned at the center of the base hole 2.

Next, a hose is connected to the end of the injection nozzle 5 on the side protruding from the base hole 2, and the liquid grout material 6 is fed into the injection nozzle 5 using a pump or the like. Grout 6
Although not particularly limited, cement prepared by mixing sand, an admixture, water and the like can be used. The grout material 6 is injected into the base hole 2 from the tip of the injection nozzle 5 as indicated by an arrow a in FIG. 1B, and the grout material 6 injected into the base hole 2 is hermetically sealed by the sealing material 3. The liquid is accumulated in the lower part of the base hole 2 and filled in the base hole 2 so that the liquid level thereof rises sequentially. At this time, as the liquid level of the grout material 6 rises, the air in the base hole 2 is displaced by the pipe-shaped lock bolt 4 as shown by the arrow B.
And is discharged from the opening at the lower end of the lock bolt 4 protruding from the base hole 2 as shown by the arrow C.

As described above, the air in the base hole 2 is
The grout material 6 is discharged through the lock bolts 4 as the grout material 6 is injected, so that the air is not trapped in the ground hole 2, and the grout material 6 can be filled deep into the upper end of the ground hole 2. Things. When the grout material 6 reaches the inside of the upper end of the base hole 2 and exceeds the upper end of the lock bolt 4, the grout material 6
As shown by the arrow (c), it flows into the lock bolt 4 from its upper end, and comes out of the lower end opening of the lock bolt 4 protruding from the base hole 2 as shown by an arrow E. If the grout material 6 comes out from the lower end of the lock bolt 4 in this way, it means that the grout material 6 has been filled in the base hole 2, so that the grout material 6 injection is stopped at this point. I just need. Although the filling state of the grout material 6 into the base hole 2 cannot be visually checked from the outside, the grout material 6 comes out from the lower end of the lock bolt 4 and the grout material 6 It can be confirmed that the grout material 6 has been filled, and the grout material 6 may be insufficiently injected into the base hole 2 or may be insufficiently filled.
Can be prevented from being excessively injected and the sealing material 3 being pushed downward from the base hole 2 and coming off.

After the grout material 6 is filled in the base hole 2 as described above, the grout material 6 is cured. When the grout material 6 is hardened, the lock bolt 4 is fixed to the base hole 2 by the hardened grout material 6. After the grout material 6 has hardened, the sealing material 3 and the injection nozzle 5 are removed from the base hole 2 as shown in FIG. By removing the sealing material 3 and the injection nozzle 5, the opening of the base hole 2 becomes a concave portion, but does not greatly affect the fixing strength of the lock bolt 4 by the grout material 6. If necessary, the grout material 6a may be applied and filled in this portion to fill it.

Then, the plate 7 provided with the through hole 17 in the center is inserted into the end of the lock bolt 4 protruding from the base hole 2 through the through hole 17, and the nut 9 is further fitted to the male screw 8 of the lock bolt 4. Screw together. By screwing and tightening the nut 9 in this manner, the plate 9 is
Is pressed, and the plate 7 is pressed against the opening edge of the base hole 2 as shown in FIG. Thus, the lock bolt 4
Can be completed.

[0018]

As described above, according to the present invention, the opening of the base hole is closed with a sealing material, and a lock bolt and an injection nozzle formed in a pipe shape are inserted into the base hole through the sealing material, and the grout material is inserted from the injection nozzle. The grout material is injected into the ground hole, and the grout material is filled in the ground hole, and the grout material is hardened.When the grout material is injected into the ground hole from the injection nozzle, the air in the ground hole is a pipe-shaped rock bolt. Through which the grout material can be injected without trapping air in the base hole, and the grout material can be filled deep into the upper end of the base hole. The rock bolt can be fixed to the ground hole with high strength.

Further, according to the invention of claim 2, when the grout material is injected into the base hole from the injection nozzle, the grout material is injected when the grout material comes out from the end of the lock bolt protruding from the base hole. The grout material can be stopped after it is confirmed that the grout material has been filled into the base hole beyond the upper end of the lock bolt. Can be injected.

[Brief description of the drawings]

FIG. 1 shows an example of an embodiment of the present invention,
(A), (b), (c), (d), and (e) are cross-sectional views in respective steps.

FIG. 2A is a perspective view of an example of a lock bolt used in the embodiment, and FIG. 2B is a perspective view of a lock bolt fall prevention device.

FIGS. 3A and 3B show a sealing material used in the embodiment, in which FIG. 3A is a perspective view and FIG. 3B is a cross-sectional view.

FIG. 4 is an enlarged sectional view of a part of FIG.

FIG. 5 shows a conventional example, in which (a), (b),
(C), (d) is sectional drawing in each process.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wall surface 2 Ground hole 3 Seal material 4 Lock bolt 5 Injection nozzle 6 Grout material 7 Plate 8 Male screw 9 Nut

Claims (2)

[Claims] 1. A base hole that opens downward on a wall surface of an excavated lateral hole, and the opening of the base hole is closed with a sealing material.
After inserting the lock bolt and injection nozzle formed in a pipe shape into the base hole through this seal material, inject the grout material into the base hole from the injection nozzle, fill the inside of the base hole with the grout material, and cure the grout material, The plate is inserted into the end of the lock bolt projecting from the base hole, the plate is brought into contact with the opening edge of the base hole, and a nut is screwed into a male screw provided on the outer periphery of the end of the lock bolt projecting from the base hole. A method for applying a lock bolt, wherein a plate is pressed against an opening edge of a base hole. 2. The grouting material is injected from the injection nozzle into the base hole, and when the grout material comes out from the end of the lock bolt protruding from the base hole, the injection of the grout material is stopped. A method for installing the lock bolt according to claim 1.