JPH07279577A - Prelining for tunnel - Google Patents

Abstract

PURPOSE:To stabilize the bank in front of a pit face in precedence with the tunnel excavation, as for the tunnel construction having the bad ground quality condition. CONSTITUTION:A bank Y is drilled by the bit 13 of a twist drill 12 installed at the top end of an inner pipe, without applying a percussion, on an outer pipe 11, by using a double pipe P consisting of an inner pipe 10 and the outer pipe 11. After the drilling, the twist drill 13 and the inner pipe 10 are pulled out, leaving the bit 13 and the outer pipe 11 as reinforced pipe, and the grouting material, is poured into the outside and the inside of the outer pipe.

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 pre-lining method is also called a pre-receiving method and is one of the auxiliary methods for stabilizing the ground in large-section tunnel construction under poor geological conditions.

In recent years, there is a tendency for construction work to be performed in places with poor geological conditions, and various receiving methods have been developed. An outline of the method is shown in FIG. 17 to FIG. The reinforcing pipe P such as
By placing it over 0 ° and injecting a reinforcing material C such as cement milk into the space 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 before the tunnel excavation. In the figure, H ₁ is an air supply tube for sending air for discharging the drilling slurry, and H ₂ is an air vent tube.

As for this preparatory construction method, various construction methods have been developed in accordance with the conditions of the ground, and each has one of the following advantages.

For example, the Trevi tube method uses an expensive large-scale special machine, and it takes time to move in a tunnel.
Construction costs are high because a special pipe is used as a reinforcing material. Further, the perforation performance of the gravel layer is remarkably deteriorated, and in some cases, the perforation may become impossible.

The AGF method is a relatively inexpensive method. The feature of this construction method is that a steel pipe with a diameter of about 100 mm is driven by a double pipe method using a diameter-expanding bit. A hydraulic jumbo is used as the punch.

After the driving is completed, the inner tube and the diameter-expanding bit are pulled out, and then a curing agent such as silica resin is injected. Here, many small holes are made in the outer circumference of the pipe, and the hardening agent permeates into the ground around the pipe from here. That is, the steel pipe also plays a role of a strainer in the chemical liquid injection.
However, since the packer is at the mouth during injection, the pressure does not rise at the tip and it is difficult for the packer to penetrate into the ground, and the degree of penetration of the curing agent into the outer periphery of the pipe is confirmed by measuring the injection amount, but it is not sufficient. There are drawbacks.

Further, since a drill jumbo is used and a drilling method using a top hammer is used, there is a limit to the diameter of the pipe for placing, and the diameter cannot be increased so much. Therefore, it is weak against the gravel layer.

Further, the diameter-expanding bit also lacks reliability.

[0010]

The problems of the above-mentioned conventional receiving method are summarized as follows: (1) As a reinforcing material, a special one having a hole drilled on the outer periphery of the pipe is used, which is expensive.

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

(3) The perforation performance of the gravel layer is poor, and in some cases, it becomes impossible to perforate.

(4) In the case of the construction method utilizing the tunnel jumbo (AGF construction method) in order to give the construction machine versatility and mobility, the diameter-expansion bit by the double pipe is adopted. Somewhat unreliable in reliability (for gravel layer).

(5) When a large rotary percussion type top hammer is used in correspondence with the gravel layer, the pipe is hit and a thick pipe is required, so that the reinforcing material becomes expensive. In addition, when a large-diameter pipe is to be placed, the weight becomes large, which causes a problem in handling.

And the like.

The present invention has been made for the purpose of solving such problems.

[0017]

According to the present invention, a reinforcing pipe such as a steel pipe is laid along the outer circumference of a tunnel arch in a tunnel construction under bad geological conditions, and a gap between the reinforcing pipe and the ground is formed. In addition, by injecting a hardening agent such as cement milk into the inside of the reinforcing pipe, an auxiliary construction method that stabilizes the ground in front of the cutting face prior to tunnel excavation. A double pipe consisting of an outer pipe with a smaller diameter than that is rotated, and the ground is drilled by down the hole drill, and after the drilling is completed, the lost bit and the outer pipe to be a reinforcing material are left in the ground, and the down the hole drill and the inner pipe are Withdrawing and then injecting the curing agent.For the injection of the curing agent, first place the packer on the tip of the tube and inject it under pressure while rotating the outer tube to inject outside the reinforcing tube, and then inject it with injection pressure. It is adapted to perform a reinforcing tube injection while down on the over to the mouth side.

[0018]

[Operation] An umbrella-shaped reinforcing material arch is formed in the ground in front of the face of the face before the tunnel excavation, and this reinforcing material arch enables 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 for rotation, and the down-the-hole drill is used for perforation, and the outer pipe is simply rotated after the rear pipe. Can be used with a commercially available thin-walled gas pipe because it does not hit.

Since the hardening agent permeates along the outer circumference of the outer tube, which serves as a reinforcing material, and comes out from the mouth, the injection state of the hardening agent can be visually confirmed, so that the hardening can be performed reliably.

Further, since the injection in the reinforcing pipe is performed while the packer is 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 for carrying out the present invention. As an existing anchor drill, a crawler or wheel type carriage, in the illustrated example, a crawler type carriage 1 is a mast. A rock drilling machine 7 having a pipe 2 and a boom 4 and connected with a double pipe, the details of which will be described later, moves linearly on the mast 2 while rotating the pipe. The mast 2 is elevated by the hydraulic cylinders 3, 5, and 6 via the boom 4, and as shown in FIG. 4, the mast 2 is swung within an angle θ, for example, 120 °.

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

The spraying robot F carried into the tunnel T
Then, the concrete is sprayed onto the mirror R (Fig. 5). Next, the work vehicle K is brought close to the mirror portion R on which the concrete has been sprayed, and the above-described punching machine J is arranged behind it to install the work machine (FIG. 6). Next, the double pipe P suspended by the pipe handling vehicle L is set on the perforator J, and the perforator J is driven to perform perforation and pipe propulsion (FIG. 7). Then, the drill and the inner pipe are recovered by leaving the lost bit and the outer pipe serving as a reinforcing material in the ground (FIG. 8). Then, the piercing machine J is removed, and the grout material vehicle M feeds the grout material under pressure 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.
Outer tube injection and in-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 having 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 unevenness and the hole 14, and they are connected so that they 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 above-mentioned prelining drilling machine J. The rock drilling machine 7 is operated to rotationally drive the double pipe P to punch the natural ground Y, and at the same time, the double pipe P is propelled into the natural ground Y.
At that time, air is ejected from the hole 15 provided in the bit 13, and the slime S is discharged by this air (FIG. 1).
1). At this time, perforation is performed by the down-the-hole drill 12, the outer tube 11 is simply rotated afterward, and the outer tube 11 serving as a reinforcing member is not hit, so a commercially available thin gas tube can be used.

After finishing the drilling, the down the hole drill 1 with the lost bit 13 and the outer pipe 11 serving as a reinforcing material left on the ground Y.
The inner tube 10 of No. 2 is pulled out, and the hardening agent is injected.

For injection of the outer tube, a packer 17 is attached to the tip.
Insert the tube 18 with the
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 attached to the mouth of the outer tube 11.
2 (FIG. 20). A 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
While rotating, the hardening agent C such as cement milk is injected into the space between the outer tube 11 and the ground Y through the injection port 20 (FIG. 12). At that time, the hardening agent C permeates along the outer circumference of the outer tube 11 and comes out from the mouth, so that the injection can be confirmed.

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

The above-mentioned work is carried out, for example, over a range of 120 °, and an umbrella-shaped reinforcement arch A (Fig. 1) is formed in the ground in front of the face.
8) is formed. As a result, the natural ground Y is stabilized and tunnel excavation is performed without causing natural ground collapse.

FIGS. 14 and 15 show how the drill and the bit are connected to each other. The bit 13 is provided with concave and convex portions having different pitches facing each other by 180 °, and the shank rod 12S of the drill has this concave and convex portions. An uneven portion is formed on the outer periphery so as to engage with each other. By inserting the shank rod 12S into the bit 13 and rotating the shank rod 12S into the abutment portions (a) and (b) of the bit concavo-convex portion until the concavo-convex portion of the shank rod abuts, the bit 13 is shank rod 1.
Bound to 2S.

FIG. 16 shows a packer 17 that can be preferably 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 it. The rubber packer bag 34 is swaged 3
It is fixed by 5, and a spiral spring 36 is provided in the packer bag body 34. The spiral spring 36 is of a Tyco type in which the central portion is made large at the ends, and the diameter of the central portion is changed by contraction and extension of the spring. A spacer 37 having a diameter slightly smaller than that of the reinforcing pipe is provided in the vicinity of the protrusion 32, and a ring 38 is attached to the screw 33 formed at the rear end of the injection pipe 30.
Is screwed in. By adjusting the ring 38 by screwing, the spring force of the spring 39 is changed so that the casing 40
The pressing force on the inner wall of the is adjusted. The outer tube 11 of the double tube P is used as the casing.

In use, when the packer is inserted into the casing, the outer peripheral projection 32 of the injection pipe 30 is pressed against the spacer 37 and further pushed. As a result, the spring 36 in the packer bag 34 extends and the spring 3
The diameter of the central portion of 6 is small, 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 central portion of the spring 36 increases, and the packer strongly presses against the inner wall of the casing 40.

[0034]

【The invention's effect】

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

(2) Since the injection state of the curing agent can be visually confirmed, it can be performed reliably.

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

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

(5) The punching machine is compact and has a small turning ability, has good workability, and is capable of punching rock bolts, water drainers, etc., and is versatile.

(6) It can be applied to rocks with bad geological conditions such as gravel layer and can be applied to a wide range.

From the above, since the construction method of the present invention can achieve high work efficiency with low equipment cost, the construction work can be significantly reduced as compared with the conventional construction method.

[Brief description of drawings]

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

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

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

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

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

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

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

FIG. 8 is a drill and inner tube recovery diagram showing the construction procedure of the construction method of the present invention.

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

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

FIG. 11 is a vertical cross-sectional view showing a punching step in the construction method of the present invention.

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

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

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

FIG. 15 is a view showing a state after connecting the bit to the shank rod.

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

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

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

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

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

[Explanation 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 injection port 21 ・ ・ ・ Pedestal 22 ・ ・ ・ Stopper P ・ ・ ・ Double pipe C ・ ・ ・ Grout S ・ ・ ・ Slurry T ・ ・ ・ Tunnel Y ・ ・ ・ Ground

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akira Higuchi 2-35 Shinozaki-cho, Edogawa-ku, Tokyo Higuchi Gikko Co., Ltd. (72) Inventor Takeo Watanabe 3-1-1 Tamata, Tamano-shi, Okayama Stocks Company Tamano Works (72) Inventor Junnori Kitagawa 5-6-4 Tsukiji, Chuo-ku, Tokyo Mitsui Engineering & Ships Co., Ltd. (72) Inventor Katsumi Maeda 5-6-4 Tsukiji, Chuo-ku, Tokyo Mitsui Engineering & Shipbuilding Within the corporation

Claims (1)

[Claims] 1. In a tunnel construction under bad geological conditions, a reinforcing pipe such as a steel pipe is placed along the outer circumference of the tunnel arch, and cement milk or the like is hardened in the space between the reinforcing pipe and the ground and inside the reinforcing pipe. In the auxiliary method of stabilizing the ground before the face of the tunnel by injecting the agent, the inner pipe with the down the hole drill with the lost bit at the tip and the outer pipe with a diameter smaller than the bit diameter are used. Rotate the heavy pipe and drill the ground with the down the hole drill, and after finishing the drilling, pull out the down the hole drill and the inner pipe leaving the lost bit and the outer pipe that will be the reinforcing material in the ground, then inject the hardening agent and cure. For agent injection, first place the packer on the tip of the tube and inject it under pressure while rotating the outer tube to infuse the outside of the tube, then reinforce it while pushing the packer down to the mouth side with the injection pressure. Tunnel pre lining method which is characterized in that the inner injection.