JP2770904B2 - Tunnel prelining method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a prelining method which is an auxiliary method for stabilizing the ground in tunnel construction with poor geological conditions.

[0002]

2. Description of the Related Art The prelining method is also referred to as a pre-installation method, and is one of auxiliary methods for stabilizing the ground in large-section tunnel construction under poor geological conditions.

[0003] In recent years, there has been a tendency to increase construction in places with poor geological conditions, and various pre-installation methods have been developed. The outline of the method is as shown in Figs. Of the reinforcing pipe P at an angle θ, for example, 12
By pouring over 0 ° and injecting a reinforcing material C such as cement milk into a gap between the reinforcing pipe P and the ground Y,
This is a method of forming an umbrella-shaped reinforcing material arch A in the ground in front of the face R prior to tunnel excavation. Incidentally, the air supply tube, H ₂ H ₁ is sending air for discharging drilling slurry in the figure shows the air vent tube.

Various methods have been developed for this prior receiving method in accordance with the conditions of the ground, and each method has the following advantages.

[0005] For example, the Trevi tube method uses an expensive large dedicated machine, takes time to move in a tunnel,
Construction costs are high because special pipes are used as reinforcement. In addition, the perforation performance of the gravel layer is significantly reduced, and in some cases, the perforation becomes impossible.

Next, there is an AGF method as a relatively inexpensive method. The feature of this method is that a steel pipe with a diameter of about 100 mm is cast in a double-pipe system using an enlarged diameter bit. A hydraulic jumbo is used as the drilling machine.

After the completion of the casting, the inner tube and the enlarged bit are pulled out, and then a hardening agent such as silica resin is injected. Here, a number of small holes are formed in the outer periphery of the pipe, from which the hardener penetrates into the ground around the pipe. That is, the steel pipe also plays a role of a strainer in injecting a chemical solution.
However, at the time of injection, the packer is at the mouth, so the pressure does not increase at the tip and it is difficult to penetrate into the ground, and the degree of penetration of the hardener into the pipe outer periphery is confirmed by measuring the injection amount, but it is not sufficient There are drawbacks.

In addition, the diameter of a casting pipe is limited by a drilling method using a drill jumbo and a top hammer, so that the diameter cannot be too large. Therefore, it is weak to the gravel layer.

[0009] In addition, the diameter expansion bit also lacks reliability.

[0010]

SUMMARY OF THE INVENTION Problems to be solved by the conventional prior construction method described above can be summarized as follows: (1) As a reinforcing material, a specially-made one in which a hole is formed in the outer periphery of a pipe is used, which is expensive.

(2) It is difficult to confirm the state of penetration of the curing agent around the pipe as a reinforcing material, and the reliability is lacking.

(3) Perforation performance of the gravel layer is poor, and in some cases, perforation cannot be performed.

(4) In the case of the construction method using the tunnel jumbo (AGF construction method) in order to provide the construction machine with versatility and mobility, an enlarged bit using a double pipe is employed. There is some anxiety about reliability (in the case of gravel layer).

(5) When a rotary percussion type large top hammer is used in response to the gravel layer, the pipe is hit and a thick pipe is required, so that the reinforcing material is expensive. Further, when attempting to cast a large-diameter pipe, the weight becomes large, which causes a problem in handling.

And the like.

The present invention has been made to solve such a problem.

[0017]

According to the present invention, in a tunnel construction with poor geological conditions, a reinforcing pipe such as a steel pipe is cast along the outer periphery of the tunnel arch to form a gap between the reinforcing pipe and the ground. In addition, by injecting a hardening agent such as cement milk into the inside of the reinforcing pipe, in the auxiliary method of stabilizing the ground in front of the face prior to tunnel excavation, the inner pipe with a down the hole drill with a lost bit at the tip and the bit diameter Rotate a double pipe consisting of an outer pipe with a smaller diameter than the outer pipe, drill the ground with a down-the-hole drill, and after the drilling is completed, leave the lost pipe and the outer pipe that serves as a reinforcing material in the ground to remove the down-the-hole drill and the inner pipe. Pull out and then inject hardener.For injecting hardener, first place the packer at the tip of the pipe, pressurize and inject while rotating the outer pipe, perform outer injection of the reinforcing pipe, and then pack with the injection pressure. It is adapted to perform a reinforcing tube injection while down on the over to the mouth side.

[0018]

An umbrella-shaped reinforcing material arch is formed in the ground in front of the face prior to tunnel excavation, and the reinforcing material arch enables a large-section tunnel excavation even in poor geological conditions.

In the construction, the existing rock drill is connected to the rear end of the pipe and driven to rotate. The drilling is performed by a down-the-hole drill, and the outer pipe is simply rotated by the trailing edge. Since no impact is applied, a commercially available thin gas pipe can be used.

Since the hardener penetrates along the outer periphery of the outer tube serving as a reinforcing material and emerges from the mouth, the injection state of the hardener can be visually confirmed, so that the hardener can be surely performed.

Further, since the injection into the reinforcing pipe is performed while the packer is being pushed down by the injection pressure, the pressure is constantly applied to the curing agent, and the injection effect can be enhanced.

[0022]

1 to 3 show an example of a prelining drilling machine J embodying the present invention. Like a conventional anchor drill, a crawler or wheel type bogie, in the illustrated example, a crawler type bogie 1 has a mast. 2 and a boom 4, and on the mast 2, a rock drill 7 to which a double pipe described in detail below is connected moves linearly while rotating the pipe. The mast 2 is raised by hydraulic cylinders 3, 5, and 6 via a boom 4, and is turned within a range of an angle θ, for example, 120 °, as shown in FIG.

First, the outline of the construction procedure will be described with reference to FIGS.

The spraying robot F carried into the tunnel T
Concrete spraying of the mirror part R is carried out (FIG. 5). Next, the work vehicle K is brought close to the mirror portion R where the concrete spraying has been completed, and the above-described drilling machine J is disposed behind the work portion K to install the work machine (FIG. 6). Next, the double pipe P suspended by the pipe handling vehicle L is set on the drill J, and the drill J is driven to perform drilling and pipe propulsion (FIG. 7). Next, the drill and the inner tube are recovered while leaving the lost bit and the outer tube serving as a reinforcing material in the ground (FIG. 8). Next, the drilling machine J is removed, and the grout material is pressure-fed by the grout equipment vehicle M to perform grout injection (FIG. 9). Then remove the equipment (Fig. 1
0). This is repeated to form an umbrella-shaped reinforcing material arch A (FIG. 18) in the ground in front of the face R.

Next, referring to FIG. 11 to FIG.
The outer tube injection and the inner tube injection will be described in detail.

The double pipe P is composed of an inner pipe 10 and an outer pipe 11, and a down-the-hole drill (hammer) 12 with a lost bit 13 is attached to the tip of the inner pipe 10.
The attachment of the drill 12 and the bit 13 is an engagement between the concave and convex and the hole 14, and is connected so that it can be easily attached and detached in a manner described later in detail. The outer tube 11 has a smaller diameter than the bit diameter of the bit 13. The double pipe P is connected via a swivel 16 to the rock drilling machine 7 (FIG. 1) of the prelining drill J described above. The rock drill 7 is actuated to rotate and drive the double pipe P to pierce the ground Y, and at the same time to push the double pipe P into the ground Y.
At this time, air is blown out from a hole 15 provided in the bit 13 and the slime S is discharged by the air (FIG. 1).
1). At this time, the perforation is performed by the down-the-hole drill 12 and the outer tube 11 simply rotates in a backward direction. Since the outer tube 11 serving as a reinforcing material is not hit, a commercially available thin gas tube can be used.

After the drilling is completed, the lost bit 13 and the outer pipe 11 serving as a reinforcing material are left in the ground Y to make the down-the-hole drill 1
The inner tube 10 of 2 is pulled out and a hardener is injected.

For outer tube injection, packer 17
Is inserted into the outer tube 11 and the packer 17 is inserted.
Is set at the tip of the outer tube 11, the pedestal 21 is placed on the tunnel insertion surface of the outer tube 11, and the stopper 2 is placed at the mouth of the outer tube 11.
2 (FIG. 20) are provided. The hose 19 passing through the pipe 18 is connected to the pump side of the grout equipment vehicle M (FIG. 9), and the outer pipe 11
Is rotated, the hardener C such as cement milk is injected into the space between the outer pipe 11 and the ground Y through the injection port 20 (FIG. 12). At that time, the curing agent C permeates along the outer periphery of the outer tube 11 and comes out from the mouth, so that the injection can be confirmed.

For in-pipe injection, packer 1
7 retreats to the mouth side and injects hardening agent C such as cement milk into outer tube 11 (FIG. 13). When the packer 17 reaches the mouth, it is stopped by the stopper 22.

The above operation is performed, for example, over a range of 120 °, and an umbrella-shaped reinforcing material arch A (FIG.
8) is formed. Thereby, the ground Y is stabilized and the tunnel excavation is performed without causing the ground collapse.

FIGS. 14 and 15 show the manner of connection between the drill and the bit. In the bit 13, concavo-convex portions having different pitches are formed inside the bit 13 so as to face each other at 180 °. An uneven portion is formed on the outer periphery so as to mesh with the shape. By inserting the shank rod 12S into the bit 13 and rotating the shank rod 1 until the shank rod uneven portion abuts against the abutting portions (a) and (b) of the bit uneven portion, the bit 13 is
Combined with 2S.

FIG. 16 shows a packer 17 which can be suitably used in the present invention. A check valve 31 is provided at the tip of the injection pipe 30 and a projection 32 is formed behind the check valve 31. Rubber packer bag 34 is caulking 3
5 and a helical spring 36 is provided in the packer bag 34. The helical spring 36 is of a Tyco type having a large center portion with a large end portion, and utilizes the fact that the diameter of the center portion changes due to contraction and expansion of the spring. A spacer 37 having a slightly smaller diameter than the reinforcing pipe is provided in front of the projection 32 and a ring 33 is formed on a screw 33 formed at the rear end of the injection pipe 30.
The ring 38 is screwed in and adjusted to change the spring force of the spring 39 so that the casing 40
The pressing force against the inner wall is adjusted. The outer tube 11 of the double tube P is employed as a casing.

At the time of use, when inserting the packer into the casing, the packer is further pushed in with the outer peripheral projection 32 of the injection pipe 30 abutting against the spacer 37. As a result, the spring 36 in the packer bag body 34 expands and the spring 3
The diameter of the central portion of the casing 6 is reduced, and the packer is prevented from being strongly pressed against the inner wall of the casing 40. During injection, the outer peripheral projection 32 of the injection pipe 30 is separated from the spacer 37, the diameter of the center of the spring 36 is increased, and the packer is strongly pressed against the inner wall of the casing 40.

[0034]

【The invention's effect】

(1) As a reinforcing material, a commercially available thin gas pipe having a relatively large diameter can be used without any special processing.

(2) The state of injection of the curing agent can be confirmed visually, so that it can be surely performed.

(3) Since the injection is performed while constantly applying pressure to the curing agent, the injection effect can be improved.

(4) Since the number of castings can be reduced, the construction period is shortened.

(5) The drilling machine is compact, has a small workability, has good workability, and is also versatile because it can also be used for drilling rock bolts and draining water.

(6) The present invention can be applied to a ground with bad geological conditions, such as a gravel layer, and can be used in a wide range.

From the above, the construction method of the present invention can achieve high working efficiency with low equipment cost, so that the construction can be greatly reduced as compared with the conventional construction method.

[Brief description of the drawings]

FIG. 1 is a side view showing an example of a drilling machine used in the method of the present invention.

FIG. 2 is a plan view showing an example of a drilling machine used in the method of the present invention.

FIG. 3 is a front view showing an example of a punch used in the method of the present invention.

FIG. 4 is a front view showing a construction range.

FIG. 5 is a mirror concrete spraying diagram showing a construction procedure of the method of the present invention.

FIG. 6 is a work machine installation diagram showing a construction procedure of the method of the present invention.

FIG. 7 is a drilling and pipe propulsion diagram showing a construction procedure of the method of the present invention.

FIG. 8 is a drawing of a drill and an inner pipe showing a construction procedure of the method of the present invention.

FIG. 9 is a grout injection diagram showing the construction procedure of the method of the present invention.

FIG. 10 is a machine removal view showing a construction procedure of the construction method of the present invention.

FIG. 11 is a longitudinal sectional view showing a drilling step in the method of the present invention.

FIG. 12 is a longitudinal sectional view showing an outer tube injection step in the method of the present invention.

FIG. 13 is a longitudinal sectional view showing an inner pipe injection step in the method of the present invention.

FIG. 14 is a diagram showing a state before a bit is connected to a shank rod before connection.

FIG. 15 is a view showing a state in which a bit is coupled to a shank rod after coupling;

FIG. 16 is a detailed vertical sectional view showing an example of a packer used in the method of the present invention.

FIG. 17 is a longitudinal sectional view showing an outline of a tunnel prelining method.

FIG. 18 is a cross-sectional view showing an outline of a tunnel prelining method.

FIG. 19 is a detailed vertical sectional view of a main part showing an outline of a tunnel prelining method.

FIG. 20 is a diagram showing a stopper used in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Inner tube 11 ... Outer tube 12 ... Hammer 12S ... Shank rod 13 ... Lost bit 14 ... Hole 16 ... Swivel 17 ... Packer 18 ... Tube 19 ... Hose 20 ... Grout inlet 21 ... Pedestal 22 ... Stopper P ... Double tube C ... Grout S ... Slurry T ... Tunnel Y ... Land

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Akira Higuchi 2-35, Shinozaki-cho, Edogawa-ku, Tokyo Inside Higuchi Engineering Co., Ltd. (72) Inventor Takeo Watanabe 3-1-1, Tamano, Tamano-shi, Okayama Mitsui (72) Inventor Junnori Kitagawa 5-6-4 Tsukiji, Chuo-ku, Tokyo Mitsui Engineering & Shipbuilding Co., Ltd. (72) Katsumi Maeda 5-6-4 Tsukiji, Chuo-ku, Tokyo Mitsui Engineering & Shipbuilding Co., Ltd. Incorporated (58) Fields surveyed (Int.Cl. ⁶ , DB name) E21D 9/04

Claims (1)

(57) [Claims] In a tunnel construction with poor geological conditions, a reinforcing pipe such as a steel pipe is cast along the outer periphery of a tunnel arch to harden cement milk or the like in a gap between the reinforcing pipe and the ground and inside the reinforcing pipe. In the auxiliary construction method to stabilize the ground in front of the cutting face prior to tunnel excavation by injecting an agent, an inner pipe equipped with a down-the-hole drill with a lost bit at the tip and an outer pipe smaller in diameter than the bit diameter Rotate the heavy pipe to pierce the ground with a down-the-hole drill, and after the drilling is completed, pull out the down-the-hole drill and the inner pipe, leaving the lost bit and the outer pipe that is the reinforcing material in the ground, then inject a hardener and cure. For agent injection, first place the packer at the end of the tube, press the tube while rotating the outer tube to perform injection outside the reinforcing tube, and then reinforce while pushing down the packer to the mouth with the injection pressure. Tunnel pre lining method which is characterized in that the inner injection.